This invention relates to dipeptide compounds which are growth hormone secretagogues and are useful for the treatment and prevention of osteoporosis and/or frailty.
Growth hormone (GH), which is secreted from the pituitary gland, stimulates growth of all tissues of the body that are capable of growing. In addition, growth hormone is known to have the following basic effects on the metabolic processes of the body:
1. Increased rate of protein synthesis in substantially all cells of the body;
2. Decreased rate of carbohydrate utilization in cells of the body: and
3. Increased mobilization of free fatty acids and use of fatty acids for energy.
Deficiency in growth hormone results in a variety of medical disorders. In children, it causes dwarfism. In adults, the consequences of acquired GH deficiency include profound reduction in lean body mass and concomitant increase in total body fat, particularly in the truncal region. Decreased skeletal and cardiac muscle mass and muscle strength lead to a significant reduction in exercise capacity. Bone density is also reduced. Administration of exogenous growth hormone has been shown to reverse many of the metabolic changes. Additional benefits of therapy have included reduction in LDL cholesterol and improved psychological well-being.
In cases where increased levels of growth hormone were desired, the problem was generally solved by providing exogenous growth hormone or by administering an agent which stimulated growth hormone production and/or release. In either case the peptidyl nature of the compound necessitated that it be administered by injection. Initially the source of growth hormone was the extraction of the pituitary glands of cadavers. This resulted in an expensive product, and carried with it the risk that a disease associated with the source of the pituitary gland could be transmitted to the recipient of the growth hormone (e.g., Jacob-Creutzfeld disease). Recently, recombinant growth hormone has become available which, while no longer carrying any risk of disease transmission, is still a very expensive product which must be given by injection or nasal spray.
Most GH deficiencies are caused by defects in GH release, not primary defects in pituitary synthesis of GH. Therefore, an alternative strategy for normalizing serum GH levels is by stimulating its release from somatotrophs. Increasing GH secretion can be achieved by stimulating or inhibiting various neurotransmitter systems in the brain and hypothalamus. As a result, the development of synthetic growth hormone-releasing agents to stimulate pituitary GH secretion are being pursued, and may have several advantages over expensive and inconvenient GH replacement therapy. By acting along physiologic regulatory pathways, the most desirable agents would stimulate pulsatile GH secretion, and excessive levels of GH that have been associated with the undesirable side effects of exogenous GH administration would be avoided by virtue of intact negative feedback loops.
Physiologic and pharmacologic stimulators of GH secretion, which include arginine, L-3,4-dihydroxyphenylalanine (L-DOPA), glucagon, vasopressin, and insulin induced hypoglycemia, as well as activities such as sleep and exercise, indirectly cause growth hormone to be released from the pituitary by acting in some fashion on the hypothalamus perhaps either to decrease somatostatin secretion or to increase the secretion of the known secretagogue growth hormone releasing factor (GHRF) or an unknown endogenous growth hormone-releasing hormone or all of these.
Obesity is a major risk factor for diabetes, and a large fraction of NIDDM patients are obese. Both conditions are characterized by elevated circulating insulin levels and suppressed GH levels. GH treatment of GH-deficient adults (Jorgensen, J. O. L., et al., Lancet 1:1221 (1989)), obese women (Richelsen, B., et al., Am J Physiol, 266: E211 (1994)) and elderly men (Rudman, D., et al, Horm Res 36 (Suppl 1):73 (1991)) has been shown to produce increases in lean body, hepatic and muscle mass while decreasing fat mass. Thus, GH therapy for obesity would seem attractive except for the diabetogenic effects of GH.
An alternative to exogenous GH administration is therapy that stimulates endogenous GH secretion. It has been shown that a substantial pituitary reserve of GH is present in pituitary-intact GH-deficient patients and the elderly so that decreased serum GH levels are due to hyposecretion.
Hyposecretion of GH in several clinical settings (obesity, aging, glucocorticoid suppression) is relatively resistant to stimulation by GHRH (Gertz, B. J., et al., J Clin Endocrinol Metab, 79:745 (1994); Arvat, E., et al., J Clin Endocrinol Metab, 79:1440 (1994); Maccario, M., et al., Metabolism, 44:134 (1995)). In contrast, administration of a GHRP or combined administration of GHRH and a GHRP in these patients can elicit a robust GH response (Aloi, J. A., et al., J Clin Endocrinol Metab, 79:943; (1994)). Single dose studies of GHRPS have demonstrated the absence of an acute effect on circulating insulin or glucose levels. Insulin and glucose have generally not been monitored in chronic studies except to document the absence of unfavorable changes (Jacks, T., et al., J Endocrinol. 143:399 (1993)).
Prior to the present invention, the use of GHRPs or GHRP mimetics to improve glycemic control has not specifically been explored. The method of treating insulin resistance in a mammal comprising the administration of a compound of Formula I of this invention is practiced preferentially in patients who have a functional hypothalamic-pituitary axis capable of GH secretory responses to GHRPs and who have pancreatic beta-cells capable of secreting insulin.
Other compounds have been developed which stimulate the release of endogenous growth hormone such as analogous peptidyl compounds related to GRF or the peptides of U.S. Pat. No. 4,411,890. These peptides, while considerably smaller than growth hormones, are still susceptible to various proteases. As with most peptides, their potential for oral bioavailability is low.
WO 94/13696 refers to certain spiropiperidines and homologues which promote release of growth hormone. Preferred compounds described therein are of the general structure shown below. 
WO 94/11012 refers to certain dipeptides that promote release of growth hormone. These dipeptides have the general structure 
where L is 
The compounds of WO 94/11012 and WO 94/13696 are reported to be useful in the treatment of osteoporosis in combination with parathyroid hormone or a bisphosphonate.
PCT publication WO 97/09060 discloses the use of growth hormone releasing hormone or a functional analog thereof in the treatment of insulin resistance In mammals.
This invention provides compounds of the formula: 
or a stereoisomeric mixture thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomer thereof, or a prodrug of such compound, mixture or isomer thereof, or a pharmaceutically acceptable salt of the compound, mixture, isomer or prodrug,
wherein
HET is a heterocyclic moiety selected from the group consisting of 
d is 0, 1 or 2;
e is 1 or 2;
A is a divalent radical, where the left hand side of the radical as shown below is connected to Cxe2x80x3 and the right hand side of the radical as shown below is connected to Cxe2x80x2, selected from the group consisting of
xe2x80x94NR2xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94NR2xe2x80x94S(O)2xe2x80x94NR2xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94S(O)2xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94S(O)2xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94Nxe2x95x90C(R11)xe2x80x94NR2xe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R11)xe2x95x90Nxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94C(R11)xe2x95x90Nxe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94N(R12)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR 12xe2x80x94,
xe2x80x94Nxe2x95x90C(R11)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94S(O)2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94,
xe2x80x94Oxe2x80x94C(R9T10)xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94 and
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94S(O)2NR2xe2x80x94;
Q is a covalent bond or CH2;
W is CH or N;
X is CR9R10, Cxe2x95x90CH2 or Cxe2x95x90O;
Y is CR9R10, O or NR2;
Z is Cxe2x95x90O, Cxe2x95x90S or S(O)2;
G1 is hydrogen, halo, hydroxy, nitro, amino, cyano, phenyl, carboxyl, xe2x80x94CONH2, xe2x80x94(C1-C4)alkyl optionally independently substituted with one or more phenyl, one or more halogens or one or more hydroxy groups, xe2x80x94(C1-C4)alkoxy optionally independently substituted with one or more phenyl, one or more halogens or one or more hydroxy groups, xe2x80x94(C1-C4)alkylthio, phenoxy, xe2x80x94COO(C1-C4)alkyl, N,N-di-(C1-C4)alkylamino, xe2x80x94(C2-C6)alkenyl optionally independently substituted with one or more phenyl, one or more halogens or one or more hydroxy groups, xe2x80x94(C2-C6)alkynyl optionally independently substituted with one or more phenyl, one or more halogens or one or more hydroxy groups, xe2x80x94(C3-C6)cycloalkyl optionally independently substituted with one or more (C1-C4)alkyl groups, one or more halogens or one or more hydroxy groups, xe2x80x94(C1-C4)alkylamino carbonyl or di-(C1-C4)alkylamino carbonyl;
G2 and G3 are each independently selected from the group consisting of hydrogen, halo, hydroxy, xe2x80x94(C1-C4)alkyl optionally independently substituted with one to three halo groups and xe2x80x94(C1-C4)alkoxy optionally independently substituted with one to three halo groups;
R1 is hydrogen, xe2x80x94CN, xe2x80x94(CH2)qN(X6)C(O)X6, xe2x80x94(CH2)qN(X6)C(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2X6, xe2x80x94(CH2)qN(X6)C(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qC(O)OX6, xe2x80x94(CH2)qC(O)O(CH2)txe2x80x94A1, xe2x80x94(CH2)qOX6, xe2x80x94(CH2)qOC(O)X6, xe2x80x94(CH2)qOC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qOC(O)N(X6)(CH2)tA1, xe2x80x94(CH2)qOC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)X6, xe2x80x94(CH2)qC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)OX6, xe2x80x94(CH2)qN(X6)S(O)2N(X6)(X6), xe2x80x94(CH2)qS(O)mX6, xe2x80x94(CH2)qS(O)m(CH2)txe2x80x94A1, xe2x80x94(C1-C10)alkyl, xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl, xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(C1-C6)alkyl, xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94A1 or xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94(C3-C7)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl or 1, 2 or 3 fluoro groups;
Y1 is O, S(O)m, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94Cxe2x89xa1Cxe2x80x94, xe2x80x94N(X6)C(O)xe2x80x94, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94C(O)Cxe2x80x94, xe2x80x94OC(O)N(X6)xe2x80x94 or xe2x80x94OC(O)xe2x80x94;
q is 0, 1, 2, 3 or 4;
t is 0, 1, 2 or 3;
said (CH2)q group and (CH2)t group in the definition of R1 are optionally independently substituted with hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl, 1, 2 or 3 fluoro groups or 1 or 2 (C1-C4)alkyl groups;
R1A is selected from the group consisting of hydrogen, F, Cl, Br, I, (C1-C6)alkyl, phenyl(C1-C3)alkyl, pyridyl(C1-C3)alkyl, thiazolyl(C1-C3)alkyl and thienyl(C1-C3)alkyl, provided that R1A is not F, Cl, Br or I when a heteroatom is vicinal to Cxe2x80x3;
R2 is hydrogen, (C1-C8)alkyl, xe2x80x94(C0-C3)alkyl-(C3-C8)cycloalkyl, xe2x80x94(C1-C4)alkyl-A1 or A1;
where the alkyl groups and the cycloalkyl groups in the definition of R2 are optionally substituted with hydroxy, xe2x80x94C(O)OX6, xe2x80x94C(O)N(X6)(X6), xe2x80x94N(X6)(X6), xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)A1, xe2x80x94C(O)(X6), CF3, CN or 1, 2 or 3 independently selected halo groups;
R3 is selected from the group consisting of A1, (C1-C10)alkyl, xe2x80x94(C1-C6)alkyl-A1, xe2x80x94(C1-C6)alkyl-(C3-C7)cycloalkyl, xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C1-C5)alkyl, xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C0-C5)alkyl-A1 and xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C1-C5)alkyl-(C3-C7)cycloalkyl;
where the alkyl groups in the definition of R3 are optionally substituted with xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX3, 1, 2, 3, 4 or 5 independently selected halo groups or 1, 2 or 3 independently selected xe2x80x94OX3 groups;
X1 is O, S(O)m, xe2x80x94N(X2)C(O)xe2x80x94, xe2x80x94C(O)N(X2)xe2x80x94, xe2x80x94OC(O)xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94CX2xe2x95x90CX2xe2x80x94, xe2x80x94N(X2)C(O)Oxe2x80x94, xe2x80x94OC(O)N(X2)xe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94;
R4 is hydrogen, (C1-C6)alkyl or (C3-C7)cycloalkyl, or R4 is taken together with R3 and the carbon atom to which they are attached and form (C5-C7)cycloalkyl, (C5-C7)cycloalkenyl, a partially saturated or fully saturated 4- to 8-membered ring having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen, or is a bicyclic ring system consisting of a partially saturated or fully saturated 5- or 6-membered ring, fused to a partially saturated, fully unsaturated or fully saturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
X4 is hydrogen or (C1-C6)alkyl or X4 is taken together with R4 and the nitrogen atom to which X4 is attached and the carbon atom to which R4 is attached and form a five to seven membered ring;
R6 is a bond or is 
where a and b are each independently 0, 1, 2 or 3;
X5 and X5a are each independently selected from the group consisting of hydrogen, CF3, A1 and optionally substituted (C1-C6)alkyl;
the optionally substituted (C1-C5)alkyl in the definition of X5 and X5a is optionally substituted with a substituent selected from the group consisting of A1, OX2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX2, (C3-C7)cycloalkyl, xe2x80x94N(X2)(X2) and xe2x80x94C(O)N(X2)(X2);
or the carbon bearing X5 or X5a forms one or two alkylene bridges with the nitrogen atom bearing R7 and R8 wherein each alkylene bridge contains 1 to 5 carbon atoms, provided that when one alkylene bridge is formed then only one of X5 or X5a is on the carbon atom and only one of R7 or R8 is on the nitrogen atom and further provided that when two alkylene bridges are formed then X5 and X5a cannot be on the carbon atom and R7 and R8 cannot be on the nitrogen atom;
or X5 is taken together with X5a and the carbon atom to which they are attached and form a partially saturated or fully saturated 3- to 7-membered ring, or a partially saturated or fully saturated 4- to 8-membered ring having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen;
or X5 is taken together with X5a and the carbon atom to which they are attached and form a bicyclic ring system consisting of a partially saturated or fully saturated 5- or 6-membered ring, optionally having 1 or 2 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen, fused to a partially saturated, fully saturated or fully unsaturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
Z1 is a bond, O or Nxe2x80x94X2, provided that when a and b are both 0 then Z1 is not Nxe2x80x94X2or O;
R7 and R8 are each independently hydrogen or optionally substituted (C1-C6)alkyl;
where the optionally substituted (C1-C6)alkyl in the definition of R7 and R8 is optionally independently substituted with A1, xe2x80x94C(O)Oxe2x80x94(C1-C6)alkyl, xe2x80x94S(O)m(C1-C6)alkyl, 1 to 5 halo groups, 1 to 3 hydroxy groups, 1 to 3 xe2x80x94Oxe2x80x94C(O)(C1-C10)alkyl groups or 1 to 3 (C1-C6)alkoxy groups; or
R7 and R8 can be taken together to form xe2x80x94(CH2)rxe2x80x94Lxe2x80x94(CH2)rxe2x80x94;
where L is C(X2)(X2), S(O)m or N(X2);
R9 and R10 are each independently selected from the group consisting of hydrogen, fluoro, hydroxy and (C1-C5)alkyl optionally independently substituted with 1-5 halo groups;
R11 is selected from the group consisting of (C1-C5)alkyl and phenyl optionally substituted with 1-3 substitutents each independently selected from the group consisting of (C1-C5)alkyl, halo and (C1-C5)alkoxy;
R12 is selected from the group consisting of (C1-C5)alkylsulfonyl, (C1-C5)alkanoyl and (C1-C5)alkyl where the alkyl portion is optionally independently substituted by 1-5 halo groups;
A1 for each occurrence is independently selected from the group consisting of (C5-C7)cycloalkenyl, phenyl, a partially saturated, fully saturated or fully unsaturated 4- to 8-membered ring optionally having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen and a bicyclic ring system consisting of a partially saturated, fully unsaturated or fully saturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen, fused to a partially saturated, fully saturated or fully unsaturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
A1 for each occurrence is independently optionally substituted, on one or optionally both rings if A1 is a bicyclic ring system, with up to three substituents, each substituent independently selected from the group consisting of F, Cl, Br, I, OCF3, OCF2H, CF3, CH3, OCH3, xe2x80x94OX6, imidazolyl, xe2x80x94C(O)N(X6)(X6), xe2x80x94C(O)OX6, oxo, (C1-C6)alkyl, nitro, cyano, benzyl, xe2x80x94S(O)m(C1-C6)alkyl, 1H-tetrazol-5-yl, phenyl, phenoxy, phenylalkyloxy, halophenyl, methylenedioxy, xe2x80x94N(X6)(X6), xe2x80x94N(X6)C(O)(X6), xe2x80x94S(O)2N(X6)(X6), xe2x80x94N(X6)S(O)2-phenyl, xe2x80x94N(X6)S(O)2X6, xe2x80x94CONX11X12, xe2x80x94S(O)2NX11X12, xe2x80x94NX6S(O)2X12, xe2x80x94NX6CONX11X12, xe2x80x94NX6S(O)2NX11X12, xe2x80x94NX6C(O)X12, thiazolyl and tetrazolyl, provided that if A1 is optionally substituted with methylenedioxy then it can only be substituted with one methylenedioxy;
where X11 is hydrogen or optionally substituted (C1-C6)alkyl;
the optionally substituted (C1-C6)alkyl defined for X11 is optionally independently substituted with phenyl, phenoxy, (C1-C6)alkoxycarbonyl, xe2x80x94S(O)m(C1-C6)alkyl, 1 to 5 halo groups, 1 to 3 hydroxy groups, 1 to 3 (C1-C10)alkanoyloxy groups or 1 to 3 (C1-C6)alkoxy groups;
X12 is hydrogen, (C1-C6)alkyl, phenyl, thiazolyl, imidazolyl, furyl or thienyl, provided that when X12 is not hydrogen, the X12 group is optionally substituted with one to three substituents independently selected from the group consisting of Cl, F, CH3, OCH3, OCF3 and CF3;
or X11 and X12 are taken together to form xe2x80x94(CH2)rxe2x80x94L1xe2x80x94(CH2)rxe2x80x94; L1 is C(X2)(X2), O, S(O)m or N(X2);
r for each occurrence is independently 1, 2 or 3;
X2 for each occurrence is independently hydrogen, optionally substituted (C1-C6)alkyl or optionally substituted (C3-C7)cycloalkyl, where the optionally substituted (C1-C6)alkyl and optionally substituted (C3-C7)cycloalkyl in the definition of X2 are optionally independently substituted with xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX3, 1 to 5 halo groups or 1-3 OX3 groups;
X3 for each occurrence is independently hydrogen or (C1-C6)alkyl;
X6 for each occurrence is independently hydrogen, optionally substituted (C1-C6)alkyl, (C2-C6)halogenated alkyl, optionally substituted (C3-C7)cycloalkyl, (C3-C7)-halogenated cycloalkyl, where optionally substituted (C1-C6)alkyl and optionally substituted (C3-C7)cycloalkyl in the definition of X6 is optionally independently mono- or di-substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, CONH2, xe2x80x94S(O)m(C1-C6)alkyl, carboxylate (C1-C4)alkyl ester or 1H-tetrazol-5-yl; or
when there are two X6 groups on one atom and both X6 are independently (C1-C6)alkyl, the two (C1-C6)alkyl groups may be optionally joined and, together with the atom to which the two X6 groups are attached, form a 4- to 9-membered ring optionally having oxygen, sulfur or NX7 as a ring member;
X7 is hydrogen or (C1-C6)alkyl optionally substituted with hydroxy;
m for each occurrence is independently 0, 1 or 2;
with the proviso that:
X6 and X12 cannot be hydrogen when attached to C(O) or S(O)2 in the form C(O)X6, C(O)X12, S(O)2X6 or S(O)2X12; and
when R6 is a bond then L is N(X2) and each r in the definition xe2x80x94(CH2)rxe2x80x94Lxe2x80x94(CH2)rxe2x80x94 is independently 2 or 3.
From herein on, the word xe2x80x9ccompoundsxe2x80x9d includes a stereoisomeric mixture thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomer thereof, or a prodrug of such compound, mixture or isomer thereof, or a pharmaceutically acceptable salt of the compound, mixture, isomer or prodrug unless otherwise more specifically stated.
A preferred group of the foregoing compounds, designated the A Group compounds, are those compounds of formula I wherein
R4 hydrogen or methyl; X4 is hydrogen;
R6 is 
xe2x80x83where Z1 is a bond and a is 0 or 1; X5 and X5a are each independently selected from the group consisting of hydrogen, CF3, phenyl and optionally substituted (C1-C6)alkyl;
where the optionally substituted (C1-C6)alkyl in the definition of X5 and X5a is optionally substituted with OX2 or A1;
where A1 in the definition of X5 and X5a is imidazolyl, phenyl, indolyl, p-hydroxyphenyl, (C5-C7)cycloalkyl, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94N(X2)(X2) or xe2x80x94C(O)N(X2)(X2);
R7 is hydrogen or (C1-C3)alkyl;
or X5 and R7 are taken together and form a (C1-C5)alkylene bridge; and
R8 is hydrogen or (C1-C3)alkyl optionally substituted with one or two hydroxy groups.
A group of compounds which is preferred among the A Group compounds, designated the B Group, are those compounds of the A Group wherein b is 0; X5 and X5a are each independently selected from the group consisting of hydrogen, (C1xe2x80x94C3)alkyl and hydroxy(C1-C3)alkyl; and
R3 is selected from the group consisting of thienyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, 1-indolyl-CH2xe2x80x94, 2-indolyl-CH2xe2x80x94, 3-indolyl-CH2xe2x80x94, 1-naphthyl-CH2, 2-naphthyl-CH2xe2x80x94, 1-benzimidazolyl-CH2xe2x80x94, 2-benzimidazolyl-CH2xe2x80x94, phenyl-(C1-C4)alkyl, 2-pyridyl-(C1-C4)alkyl-, 3-pyridyl-(C1-C4)alkyl-, 4-pyridyl-(C1-C4)alkyl-, phenyl-CH2xe2x80x94Sxe2x80x94CH2xe2x80x94, thienyl-(C1-C4)alkyl-, phenyl-(C0-C3)alkyl-CH2xe2x80x94, phenyl-CH2xe2x80x94O-phenyl-CH2xe2x80x94, phenyl-Oxe2x80x94CH2xe2x80x94CH2xe2x80x94 and 3-benzothienyl-CH2xe2x80x94;
where the aryl portion(s) of the groups defined for R3 are each optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the B Group compounds, designated the C Group, are those compounds of the B Group wherein
R4 is hydrogen; a is 0;
X5 and X5a are each independently selected from the group consisting of hydrogen, methyl or hydroxymethyl, provided that when X5 is hydrogen then X5a is not hydrogen;
R7 and R8 are each hydrogen; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, 1-naphthyl-CH2xe2x80x94, 2-naphthyl-CH2xe2x80x94, phenyl-(C1-C4)alkyl-, 2-pyridyl-(C1-C4)alkyl-, 3-pyridyl-(C1-C4)alkyl-, 4-pyridyl-(C1-C4)alkyl-, phenyl-CH2xe2x80x94Sxe2x80x94CH2xe2x80x94, thienyl-(C2-C4)alkyl-, phenyl-(C0-C3)alkyl-Oxe2x80x94CH2xe2x80x94, 3-benzothienyl-CH2xe2x80x94, thienyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and phenyl-Oxe2x80x94CH2xe2x80x94CH2xe2x80x94;
where the aryl portion(s) of the groups defined for R3 are each optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the C Group compounds, designated the D Group, are those compounds of the C Group wherein
R1 is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
A1 in the definition of R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy or 1 to 3 fluoro atoms;
q is 1 or 2; t is 1 or 2;
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, phenyl-CH2xe2x80x94Sxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, thienyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, phenyl-(CH2)3xe2x80x94 or 3-indolyl-CH2xe2x80x94;
where the carbon atom bearing the substituent R3 is of the (R)-configuration;
where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
X5 and X5a are each methyl.
A group of compounds which is preferred among the D Group compounds, designated the E Group, are those compounds of the D Group wherein HET is 
A group of compounds which is preferred among the E Group compounds, designated the F Group, are those compounds of the E Group wherein
Z is S(O)2; Q is a covalent bond; X is CH2; and
Y is CH2 or NR2;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups.
A group of compounds which is preferred among the F Group compounds, designated the G Group, are those compounds of the F Group wherein Y is CH2.
A group of compounds which is preferred among the G Group compounds, designated the H Group, are those compounds of the G Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A preferred compound of the H Group is the 3a(R,S),1(R) diastereomeric mixture, the 3a(R),1(R) diastereomer or the 3a(S),1(R) diastereomer of 2-amino-N-[2-(3a-benzyl-1,1-dioxo-hexahydro-1-thia-5,7a-diaza-inden-5-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the E Group compounds, designated the I Group, are those compounds of the E Group wherein
Z is Cxe2x95x90O; Q is a covalent bond; X is CH2; and Y is NR2;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups.
A group of compounds which is preferred among the I Group compounds, designated the J Group, are those compounds of the I Group wherein R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A preferred compound of the J Group is the 8a(R,S),1(R) diastereomeric mixture, the 8a(R),1(R) diastereomer or the 8a(S),1(R) diastereomer of 2-amino-N-[2-(8a-benzyl-2-methyl-3-oxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the E Group compounds, designated the K Group, are those compounds of the E Group wherein
Z is Cxe2x95x90O; Q is a covalent bond; X is CH2; and Y is O.
A group of compounds-which is preferred among the K Group compounds, designated the L Group, are those compounds of the K Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the L Group compounds, designated the M Group, are where the compound is the 8a(R,S),1(R) diastereomeric mixture, the 8a(R),1(R) diastereomer or the 8a(S),1(R) diastereomer of the compound selected from the group consisting of
2-amino-N-[2-(8a-benzyl-3-oxo-tetrahydro-oxazolo[3,4-a]pyrazin-7-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide,
2-amino-N-[1-benzyloxymethyl-2-oxo-2-(3-oxo-8a-thiazol-4-ylmethyl-tetrahydro-oxazolo[3,4-a]pyrazin-7-yl)-ethyl]-2-methyl-propionamide and
2-amino-N-[1-benzyloxymethyl-2-oxo-2-(3-oxo-8a-pyridin-3-ylmethyl-tetrahydro-oxazolo[3,4-a]pyrazin-7-yl)-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the E Group compounds, designated the N Group, are those compounds of the E Group wherein
Z is Cxe2x95x90O or S(O)2; Q is a covalent bond; X is Cxe2x95x90O; and Y is NR2;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups.
A group of compounds which is preferred among the N Group compounds, designated the O Group, are those compounds of the N Group wherein
Z is Cxe2x95x90O; R1 is xe2x80x94CH2xe2x80x94A1, where A1 in the definition of R1 is phenyl or pyridyl where said phenyl or pyridyl is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, 3-indolyl-CH2xe2x80x94 or thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the O Group compounds, designated the P Group, are those compounds of the O Group wherein
R2 is hydrogen or (C1-C3)alkyl where the alkyl group is optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred among the P Group compounds, designated the Q Group, are those compounds of the P Group wherein
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 or phenyl-(CH2)3xe2x80x94, where the phenyl in the definition of R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the Q Group compounds, designated the R Group, are those compounds of the Q Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, 2-pyridyl, 3-pyridyl, optionally substituted with 1-3 fluoro groups or 1-3 Chloro groups;
R2 is methyl or ethyl where the ethyl group is optionally substituted with 1-3 fluoro groups; and
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the phenyl is optionally substituted with 1-3 fluoro groups, 1xe2x80x943 Chloro groups or 1-2 CF3 groups.
A preferred compound of the R Group is the 1(R),8a(R,S) diastereomeric mixture, the 1(R),8a(R) diastereomer or the 1(R),8a(S) diastereomer of 2-amino-N-{1-(2,4-difluoro-benzyloxymethyl)-2-[1,3-dioxo-8a-pyridin-3-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide.
A group of compounds which is preferred among the R Group compounds, designated the S Group, are those compounds of the R Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl optionally substituted with 1-2 chloro groups or 1-2 fluoro groups;
R2 is methyl or xe2x80x94CH2CF3; and
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, optionally substituted with 1-3 fluoro groups, 1-3 chloro groups or 1-2 CF3 groups.
A group of compounds which is preferred among the S Group compounds, designated the T Group, are those compounds of the S Group where the compound is selected from the group consisting of
2-amino-N-[2-(8a-(R,S)-benzyl-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-1-(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide,
2-amino-N-{1-(R)-benzyloxymethyl-2-[8a-(R,S)-(4-fluoro-benzyl)-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide and
2-amino-N-{2-[8a-(R,S)-benzyl-1,3-dioxo-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-1-(R)-benzyloxymethyl-2-oxo-ethyl}-2-methyl-propionamide.
The following compounds are particularly preferred of the T Group compounds:
2-amino-N-[2-(8a-(R)-benzyl-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-1-(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide;
2-amino-N-[2-(8a-(S)-benzyl-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-1-(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide;
2-amino-N-{1-(R)-benzyloxymethyl-2-[8a-(R)-(4-fluoro-benzyl)-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-{1-(R)-benzyloxymethyl-2-[8a-(S)-(4-fluoro-benzyl)-2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-{2-[8a-(R)-benzyl-1,3-dioxo-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-1-(R)-benzyloxymethyl-2-oxo-ethyl}-2-methyl-propionamide; and
2-amino-N-{2-[8a-(S)-benzyl-1,3-dioxo-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-1-(R)-benzyloxymethyl-2-oxo-ethyl}-2-methyl-propionamide.
Another group of compounds which is preferred among the R Group compounds, designated the U Group, are those compounds of the R Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is 2-pyridyl optionally substituted with 1-2 chloro groups;
R2 is methyl or xe2x80x94CH2CF3; and
R3 is phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, optionally substituted with 1-3 fluoro groups, 1-3 chloro groups or 1-2 CF3 groups.
A group of compounds which is preferred among the U Group compounds, designated the V Group, are those compounds of the U Group where the compound is
2-amino-N-[1-(R)-benzyloxymethyl-2-(2-methyl-1,3-dioxo-8a-(R,S)-pyridin-2-ylmethyl-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide,
2-amino-N-{1-(R)-benzyloxymethyl-2-[1,3-dioxo-8a-(R,S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide,
2-amino-N-{1-(R)-(2,4-difluoro-benzyloxymethyl)-2-[1,3-dioxo-8a-(R,S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide,
2-amino-N-[2-[1,3-dioxo-8a-(R,S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-1-(R)-(2-trifluoromethyl-benzyloxymethyl)-ethyl]-2-methyl-propionamide or
2-amino-N-{1-(R)-(4-chloro-benzyloxymethyl)-2-[1,3dioxo-8a-(R,S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide.
The following compounds are particularly preferred of the V Group compounds:
2-amino-N-[1-(R)-benzyloxymethyl-2-(2-methyl-1,3-dioxo-8a-(R)-pyridin-2-ylmethyl-hexahydro-imidazo[1,5a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide;
2-amino-N-[1-(R)-benzyloxymethyl-2-(2-methyl-1,3-dioxo-8a-(S)-pyridin-2-ylmethyl-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide;
2-amino-N-{1-(R)-benzyloxymethyl-2-[1,3dioxo-8a-(R)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-{1-(R)-benzyloxymethyl-2-[1,3dioxo-8a-(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-{1-(R)-(2,4-difluoro-benzyloxymethyl)-2-[1,3-dioxo-8a-(R)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-{1-(R)-(2,4-difluoro-benzyloxymethyl)-2-[1,3dioxo-8a-(S)pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide;
2-amino-N-[2-[1,3-dioxo-8a-(R)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-1-(R)-(2-trifluoromethyl-benzyloxymethyl)-ethyl]-2-methyl-propionamide;
2-amino-N-[2-[1,3-dioxo-8a-(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-1-(R)-(2-trifluoromethyl-benzyloxymethyl)-ethyl]-2-methyl-propionamide;
2-amino-N{-1-(R)-(4-chloro-benzyloxymethyl)-2-[1,3-dioxo-8a-(R)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide; and
2-amino-N-{1-(R)-(4-chloro-benzyloxymethyl)-2-[1,3dioxo-8a-(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide.
Another group of compounds which is preferred among the E Group compounds, designated the W Group, are those compounds of the E Group wherein
Z is Cxe2x95x90O; Q is a covalent bond; X is Cxe2x95x90O; and Y is CH2.
A group of compounds which is preferred among the W Group compounds, designated the X Group, are those compounds of the W Group wherein
R1 is xe2x80x94CH2A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of fluoro, chloro, methyl, OCH3, OCF2H, OCF3 and CF3; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A preferred compound of the X Group is the 1(R), 8a(R,S) diastereomeric mixture, the 1(R),8a(R) diastereomer or the 1(R),8a(S) diastereomer of 2-amino-N-{1-benzyloxymethyl-2-[8a-(4-fluoro-benzyl)-6,8-dioxo-hexahydro-pyrrolo [1,2-a]pyrazin-2-yl]-2-oxo-ethyl}-2-methylpropionamide.
Another group of compounds which is preferred among the D Group compounds, designated the Y Group, are those compounds of the D Group wherein
HET is 
A group of compounds which is preferred among the Y Group compounds, designated the Z Group, are those compounds of the Y Group wherein
W is N; d is 1; e is 0 or 1;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups;
G1 is hydrogen, halo, hydroxy, xe2x80x94(C1-C2)alkyl optionally independently substituted with one to three halo groups or xe2x80x94(C1-C2)alkoxy optionally independently substituted with one to three halo groups;
G2 is hydrogen, halo, hydroxy, xe2x80x94(C1-C2)alkyl optionally independently substituted with one to three halo groups or xe2x80x94(C1-C2)alkoxy optionally independently substituted with one to three halo groups; and
G3 is hydrogen.
A group of compounds which is preferred among the Z Group compounds, designated the AA Group, are those compounds of the Z Group wherein
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups;
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3; and
G1, G2 and G3 are each independently hydrogen, Cl or F.
A preferred compound of the AA Group is 2-amino-N-[1-(R)-(1H-indol-3-ylmethyl)-2-oxo-2-(9-oxo-1,2,4a,9-tetrahydro-4H-3,9a-diaza-fluoren-3-yl)-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the C Group compounds, designated the AB Group, are those compounds of the C Group wherein
HET is 
A group of compounds which is preferred among the AB Group compounds, designated the AC Group, are those compounds of the AB Group wherein
X5 and X5a are each methyl; d is 1; e is 1;
R1 is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
A1 in the definition of R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy or 1 to 3 fluoro groups;
t is 1 or 2; q is 1 or 2; and
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups.
A group of compounds which is preferred among the AC Group compounds, designated the AD Group, are those compounds of the AC Group wherein
R1 is (C1-C6)alkyl optionally substituted with 1-3 fluoro groups;
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Cxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A preferred compound of the AD Group is 2-amino-N-[2-(2,3-dimethyl-4-oxo-3,5,7,8-tetrahydro-4H-pyrido[4,3-d]pyrimidin-6-yl)-1-(R)-(1H-indol-3-ylmethyl)-2-oxo-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the D Group compounds, designated the AE Group, are those compounds of the D Group wherein
HET is 
A group of compounds which is preferred among the AE Group compounds, designated the AF Group, are those compounds of the AE Group wherein
A is xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94; d is 1; e is 1;
R1 is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
A1 in the definition of R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy or 1-3 fluoro groups;
t is 1 or 2; q is 1 or 2;
R1A is hydrogen or methyl; and
R2 is hydrogen, (C1-C5)alkyl, xe2x80x94(C0-C2)alkyl-(C3xe2x80x94C8)cycloalkyl or (C1-C2)alkyl-A1, where
A1 in the definition of R2 is pyridyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred among the AF Group compounds, designated the AG Group, are those compounds of the AF Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups;
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3; and
R1A is hydrogen.
A group of compounds which is preferred among the AG Group compounds, designated the AH Group, are those compounds of the AG Group where the compound is the 3a(R,S)-7a(R,S) diastereomeric mixture, the 3a(R),7a(R) diastereomer, the 3a(S),7a(S) diastereomer, the 3a(R),7a(S) diastereomer or the 3a(S),7a(R) diastereomer of the compound selected from the group consisting of
3a-7a-2-amino-N-[2-(3a-benzyl-2-oxo-hexahydro-oxazolo[4,5-c]pyridin-5yl)-1-(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide,
3a-7a-2-amino-N-[1-(R)-benzyloxymethyl-2-(3-methyl-2-oxo-3a-pyridin-3-ylmethyl-hexahydro-oxazolo[4,5-c]pyridin-5-yl)-2-oxo-ethyl]-2-methyl-propionamide,
3a-7a-2-amino-N-[2-(3a-benzyl-3-methyl-2-oxo-hexahydro-oxazolo[4,5-c]pyridin-5-yl)-1-(R)-(1H-indol-3-ylmethyl)-2-oxo-ethyl]-2-methyl-propionamide and
3a-7a-2-amino-N-[1-(R)-benzyloxymethyl-2-oxo-2-(2-oxo-3a-pyridin-2-ylmethyl-hexahydro-oxazolo[4,5-c]pyridin-5-yl)-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the AE Group compounds, designated the AI Group, are those compounds of the AE Group wherein
A is xe2x80x94C(O)xe2x80x94NR2xe2x80x94CH2xe2x80x94, xe2x80x94C(O)xe2x80x94Oxe2x80x94CH2xe2x80x94, xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(O)xe2x80x94, xe2x80x94CH2xe2x80x94NR12xe2x80x94CH2xe2x80x94 or xe2x80x94C(O)xe2x80x94NR2xe2x80x94CH2xe2x80x94CH2xe2x80x94;
d is 1; e is 1;
R1 is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
A1 in the definition of R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy or 1-3 fluoro groups;
t is 1 or 2; q is 1 or 2;
R1A is hydrogen or methyl; and
R2 is hydrogen, (C1-C5)alkyl, xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred among the AI Group compounds, designated the AJ Group, are those compounds of the AI Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3; and
R1A is hydrogen.
A group of compounds which is preferred among the AJ Group compounds, designated the AK Group, are those compounds of the AJ Group where the compound is selected from the group consisting of
2-amino-N-[1-(R)-(1H-indol-3-ylmethyl)-2-(2-methyl-1,3-dioxo-octahydro-pyrrolo[3,4-c]pyridin-5-yl)-2-oxo-ethyl]-2-methyl-propionamide,
the 3a(R,S),1(R) diastereomeric mixture, the 3a(R),1(R) diastereomer or the 3a(S),1(R) diastereomer of 2-amino-N-[2-(3a-benzyl-3-oxo-octahydro-pyrrolo[3,4-c]pyridin-5-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide,
the 3a(R,S),1(R) diastereomeric mixture, the 3a(R),1(R) diastereomer or the
3a(S),1(R) diastereomer of 2-amino-N-[2-(3a-benzyl-3-oxo-hexahydro-furo[3,4-c]pyridin-5-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide,
the 3a(R,S),1(R) diastereomeric mixture, the 3a(R),1(R) diastereomer or the
3a(S),1(R)-diastereomer of N-[2-(2-acetyl-3a-benzyl-octahydro-pyrrolo[3,4c]pyridin-5-yl)-(1H-indol-2-ylmethyl)-2-oxo-ethyl]-2-amino-2-methyl-propionamide and
the 8a(R,S),1(R) diastereomeric mixture, the 8a(R),1(R) diastereomer or the
8a(S),1(R) diastereomer of 2-amino-N-[2-(8a-benzyl-7-methyl-8-oxo-octahydro-[2,7]naphthyridin-2-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred among the AE Group compounds, designated the AL Group, are those compounds of the AE Group wherein
R is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
A1 in the definition of R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, or 1-3 fluoro groups;
t is 1 or 2; q is 1 or 2;
R1A is hydrogen or methyl;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1-3 fluoro groups;
d is 1; e is 1; and
R9 and R10 are each hydrogen.
A group of compounds which is preferred among the AL Group compounds, designated the AM Group, are those compounds of the AL Group wherein
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups; and
R3 is selected from the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3; and
R1A is hydrogen.
Another group of compounds which is preferred among the C Group compounds, designated the AN Group, are those compounds of the C Group wherein
HET is 
Z is Cxe2x95x90O or S(O)2; Q is a covalent bond; X is Cxe2x95x90O; Y is NR2;
R2 is hydrogen, (C1-C5)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C8)cycloalkyl; where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1, 2 or 3 fluoro groups;
R1 is hydrogen; and
R3 is selected from the group consisting of phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, 3-indolyl-CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A group of compounds which is preferred among the AN Group compounds, designated the AO Group, are those compounds of the AN Group wherein Z is Cxe2x95x90O; R2 is hydrogen or (C1-C3)alkyl optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred among the AO Group compounds, designated the AP Group, are those compounds of the AO Group wherein R3 is selected from the group consisting of 3indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of methylenedioxy, F, Cl, CH3, OCH3, OCF3, OCF2H and CF3.
A preferred compound of the AP Group is 8a-(R,S)-2-amino-N-[1-(R)-(1H-indol-3-ylmethyl)-2-(2-methyl-1,3-dioxo-hexahydro-imidazo[1,5a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide.
An even more preferred compound of the AP Group is8a-(R)-2-amino-N-[1-(R)-(1H-indol-3-ylmethyl)-2-(2-methyl-1,3-dioxo-hexahydro-imidazo[1,5a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide.
Another more preferred compound of the AP Group is 8a-(S)-2-amino-N-[1-(R)-(1H-indol-3-ylmethyl)-2-(2-methyl-1,3-dioxo-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide.
This invention also provides:
methods for increasing levels of endogenous growth hormone in a human or other animal such as especially dogs, cats and horses, which comprise administering to such human or other animal an effective amount of a compound of Formula I;
pharmaceutical compositions which comprise a pharmaceutically acceptable carrier and an effective amount of a compound of Formula I;
pharmaceutical compositions useful for increasing the endogenous production or release of growth hormone in a human or other animal which comprise a pharmaceutically acceptable carrier, an effective amount of a compound of Formula I and a growth hormone secretagogue selected from the group consisting of GHRP6, Hexarelin, GHRP-1, growth hormone releasing factor (GRF), IGF-1, IGF-2 and B-HT920 or an analog thereof;
methods for treating or preventing osteoporosis and/or frailty which comprise administering to a human or other animal especially dogs, cats and horses, in need of such treatment or prevention an amount of a compound of Formula I which is effective in treating or preventing osteoporosis and/or frailty;
methods for treating or preventing diseases or conditions which may be treated or prevented by growth hormone which comprise administering to a human or other animal in need of such treatment or prevention an amount of a compound of Formula I which is effective in promoting release of endogenous growth hormone;
preferred methods of the immediately foregoing methods is where the disease or condition is congestive heart failure, frailty associated with aging or obesity;
preferred methods of the immediately foregoing methods is where the disease or condition is congestive heart failure or frailty associated with aging;
methods for accelerating bone fracture repair, attenuating protein catabolic response after a major operation, reducing cachexia and protein loss due to chronic illness such as AIDS or cancer, accelerating wound healing, or accelerating the recovery of bum patients or patients having undergone major surgery, which methods comprise administering to a mammal in need of such treatment an amount of a compound of Formula I which is effective in promoting release of endogenous growth hormone;
preferred methods of the immediately foregoing methods is for accelerating the recovery of patients having undergone major surgery or for accelerating bone fracture repair,
methods for improving muscle strength, mobility, maintenance of skin thickness, metabolic homeostasis or renal homeostasis, which methods comprise administering to a human or other animal in need of such treatment an amount of a compound of Formula I which is effective in promoting release of endogenous growth hormone;
methods for the treatment or prevention of osteoporosis and/or frailty which comprises administering to a human or other animal especially dogs, cats and horses, with osteoporosis and/or frailty effective amounts of a bisphosphonate compound and a compound of Formula I;
preferred methods of the immediately foregoing methods is where the bisphosphonate compound is alendronate or ibandronate;
methods for the treatment or prevention of osteoporosis and/or frailty which comprise administering to a human or other animal especially dogs, cats and horses, with osteoporosis and/or frailty effective amounts of estrogen or Premarin(copyright) and a compound of Formula I and, optionally, progesterone;
methods for the treatment of osteoporosis and/or frailty which comprise administering to a human or other animal especially dogs, cats and horses, with osteoporosis and/or frailty effective amounts of calcitonin and a compound of Formula I;
methods to increase IGF-1 levels in a human or other animal especially dogs, cats and horses, deficient in IGF-1 which comprise administering to a human or other animal with IGF-1 deficiency a compound of Formula I;
methods for the treatment of osteoporosis and/or frailty which comprises administering to a human or other animal especially dogs, cats and horses, with osteoporosis and/or frailty effective amounts of an estrogen agonist or antagonist and a compound of Formula I;
preferred methods of the immediately foregoing methods is where the estrogen agonist or antagonist is tamoxifen, droloxifene, raloxifene, idoxifene, cis-6-(4-fluoro-phenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; (xe2x88x92)-cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; cis-1-[6xe2x80x2-pyrrolodinoethoxy-3xe2x80x2-pyridyl]-2-phenyl-6-hydroxy-1,2,3,4-tetrahydro-naphthalene; 1-(4xe2x80x2-pyrrolidinoethoxyphenyl)-2-(4xe2x80x3-fluorophenyl)-6-hydroxy-1,2,3,4-tetrahydroisoquinoline; cis-6-(4-hydroxyphenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; or 1-(4xe2x80x2-pyrrolidinolethoxyphenyl)-2-phenyl-6-hydroxy-1,2,3,4-tetrahydro-isoquinoline
methods for enhancing growth and improving carcass quality of an animal other than humans which comprise administering to said animal an effective amount of a compound of Formula I;
methods for enhancing feed efficiency in an animal other than humans which comprise administering to said animal an effective amount of a compound of Formula I;
methods for increasing milk production in a female mammal which comprise administering to said female mammal an effective amount of a compound of Formula I;
methods for increasing piglet number, increasing pregnancy rate in sows, increasing viability of piglets, increasing weight of piglets or increasing muscle fiber size in piglets which comprise administering to a sow or piglet an effective amount of a compound of Formula I;
methods for increasing muscle mass, which comprise administering to a human or other animal such as dogs, cats, horses, cattle, pigs, chickens, turkeys, sheep and fish, in need of such treatment an amount of a compound of Formula I;
methods for promoting growth in growth hormone deficient children which comprise administering to a growth hormone deficient child a compound of Formula I;
methods for the treatment or prevention of congestive heart failure, obesity or frailty associated with aging, which comprise administering to a human or other animal in need thereof effective amounts of a functional somatostatin antagonist and a compound of Formula I;
preferred methods of the immediately foregoing methods is where the functional somatostatin antagonist is an alpha-2 adrenergic agonist and the other animal is a dog, cat or a horse;
preferred methods of the immediately foregoing methods is where the alpha-2 adrenergic agonist is clonidine, xylazine or medetomidine.
methods for treating insulin resistance in a mammal, which comprises administering to said mammal an effective amount of a compound of Formula I;
preferred methods of the immediately foregoing methods is where the condition associated with insulin resistance is type I diabetes, type II diabetes, hyperglycemia, impaired glucose tolerance or an insulin resistant syndrome; or where the condition associated with insulin resistance is associated with obesity or old age;
methods for increasing the endogenous production or release of growth hormone in a human or other animal especially dogs, cats and horses, which comprise administering effective amounts of a compound of Formula I and a growth hormone secretagogue selected from the group consisting of GHRP6, Hexarelin, GHRP-1, growth hormone releasing factor (GRF), IGF-1, IGF-2 and B-HT920 or an analog thereof;
pharmaceutical compositions useful for treating or preventing osteoporosis and/or frailty which comprise a pharmaceutically acceptable carrier, an amount of a bisphosphonate compound and an amount of a compound of Formula I;
pharmaceutical compositions useful for treating or preventing osteoporosis and/or frailty which comprises a pharmaceutically acceptable carrier, an amount of estrogen or Premarin(copyright), an amount of a compound of Formula I and, optionally, an amount of progesterone;
pharmaceutical compositions useful for treating osteoporosis and/or frailty which comprise a pharmaceutically acceptable carrier, an amount of calcitonin and an amount of a compound of Formula I;
pharmaceutical compositions useful for treating preventing congestive heart failure, obesity or frailty associated with aging, which comprise a pharmaceutically acceptable carrier, an amount of an alpha-2 adrenergic agonist and an amount of a compound of Formula I;
a preferred pharmaceutical composition of the immediately foregoing compositions is where the alpha-2 adrenergic agonist is clonidine, xylazine or medetomidine; and
methods for increasing levels of endogenous growth hormone, which comprise administering to a human or other animal in need thereof effective amounts of a functional somatostatin antagonist and a compound of Formula I.
In yet another aspect, this invention provides methods for improving muscle strength, mobility, maintenance of skin thickness, metabolic homeostasis and renal homeostasis, which comprise administering to a human or other animal especially dogs, cats and horses, in need of such treatment an amount of a compound of claim 1 which is effective in promoting release of endogenous growth hormone.
The instant compounds promote the release of growth hormone which are stable under various physiological conditions and may be administered parenterally, nasally or by the oral route.
Another group of compounds which is preferred within the E Group compounds, designated the EA Group, comprises those compounds, or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
Z is Cxe2x95x90O; Q is a covalent bond;
Y is CR9R10 
where R9 in the definition of Y is selected from the group consisting of hydrogen, fluoro, hydroxy and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups; and R10 in the definition of Y is selected from the group consisting of hydrogen, fluoro, and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups with the proviso that R10 cannot be fluoro when R9 is hydroxy;
and X is CHR9 
where R9 in the definition of X is selected from the group consisting of hydrogen, fluoro, hydroxy and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred within the EA Group compounds, designated the EB Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R3 is selected form the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3.
A group of compounds which is preferred within the EB Group compounds, designated the EC Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein
X is CH2;
Y is CR9R10 
where R9 and R10 in the definition of Y are independently selected from the group consisting of hydrogen, fluoro, and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups.
A group of compounds which is preferred within the EC Group, designated the ED Group, comprises those compounds or prodrugs of such compounds or pharmaceutically acceptable salts of the compounds or prodrugs wherein the compound is the 8a(R,S),1(R) diastereomeric mixture, the 8a(R),1(R) diastereomer or the 8a(S),1(R) diastereomer of 2-amino-N-[2-(8a-benzyl-6-oxo-hexahydro-pyrrolo[1,2-a]pyrazin-2-yl)-1-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide or 2-amino-N-[1-benzyloxymethyl-2-oxo-2-(6oxo-8a-pyridin-2-ylmethyl-hexahydro-pyrrolo[1,2-a]pyrazin-2-yl)-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred within the J Group comprises those compounds or prodrugs of such compounds or pharmaceutically acceptable salts of the compounds or prodrugs wherein the compound is the 8a(R,S),1(R) diastereomeric mixture, the 8a(R),1(R) diastereomer or the 8a(S),1(R) diastereomer of 2-amino-N-{1-benzyloxymethyl-2-oxo-2-[3oxo-8a-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-ethyl}-2-methyl-propionamide; 2-amino-N-{1-benzyloxymethyl-2-[8a-(2,4difluoro-benzyl)-3-oxo-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide; 2-amino-N-[1-benzyloxymethyl-2-oxo-2-(oxo-8a-pyridin-2-ylmethyl-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-ethyl]-2-methyl-propionamide; or 2-amino-N-[1-benzyloxymethyl-2-(2-ethyl-3-oxo-8a-pyridin-2-ylmethyl-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-oxo-ethyl]-2-methyl-propionamide.
Another group of compounds which is preferred within the Q Group compounds, designated the QA Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, 2-pyridyl, or 3-pyridyl, optionally substituted with 1-3F, 1-3 Cl;
R2 is methyl or ethyl where the ethyl group is optionally substituted with 1-3 F; and
R3 is phenyl-(CH2)3xe2x80x94, where the phenyl is optionally substituted with 1-3 F, 1-3 Cl or 1-2 CF3;
A group of compounds which is preferred within the QA Group of compounds, designated the QB Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein R1 is xe2x80x94(CH2)xe2x80x94A1 where A1 is 2-pyridyl, optionally substituted with 1-2 Cl; and
R2 is methyl or xe2x80x94CH2CF3.
A group of compounds which is preferred within the QB Group of. compounds, designated the QC Group, comprises those compounds or prodrugs of such compounds or pharmaceutically acceptable salts of the compounds or prodrugs wherein the compound is 2-amino-N-{1-(R)-[1,3-dioxo-8a-(R,S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazine-7-carbonyl]-(4-phenyl-butyl)}-2-methyl-propionamide.
An especially preferred compound within the QC Group comprises the compound or prodrugs of such compound or pharmaceutically acceptable salts of the compound or prodrugs where the compound is 2-amino-N-{1-(R)-[1,3-dioxo-8a-(R)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazine-7-carbonyl]-(4phenyl-butyl)}-2-methyl-propionamide.
Another especially preferred compound within the QC Group comprises the compound or prodrugs of such compound or pharmaceutically acceptable salts of the compound or prodrugs where the compound is 2-amino-N-{1-(R)-[1,3-dioxo-8a-(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazine-7-carbonyl]-(4-phenyl-butyl)}-2-methyl-propionamide.
Another group of compounds which is preferred within the AI Group of compounds, designated the AIA Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
A is xe2x80x94C(O)xe2x80x94NR2xe2x80x94CH2xe2x80x94;
R1 is xe2x80x94CH2xe2x80x94A1 where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
R2 is hydrogen or xe2x80x94(C1-C3)alkyl or xe2x80x94(C0-C2)alkyl-(C3-C5)cycloalkyl where the alkyl and cycloalkyl groups in the definition of R2 are optionally substituted with 1-3 fluoro groups;
R3 is selected form the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R1A is hydrogen.
A group of compounds which is preferred within the AlA Group of compounds, designated the AlB Group, comprises those compounds or prodrugs of such compounds or pharmaceutically acceptable salts of the compounds or prodrugs where the compound is the 3a(R,S),7a(R,S) diastereomeric mixture, the 3a(R),7a(R) diastereomer, the 3a(S),7a(S) diastereomer, the 3a(R),7a(S) diastereomer, or the 3a(S),7a(R) diastereomer of 2-amino-N-[2-(3a-benzyl-2-cyclopropyl-3-oxo-octahydro-pyrrolo[3,4-c]pyridin-5-yl)-1(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide; 2-amino-N-[2-(3a-benzyl-2-methyl-3oxo-octahydro-pyrrolo[3,4-c]pyridin-5-yl)-1(R)-benzyloxymethyl-2-oxo-ethyl]-2-methyl-propionamide; or 2-amino-N-[1(R)-benzyloxymethyl-2-(2-methyl-3-oxo-3a-pyridin-2-ylmethyl-octahydro-pyrrolo[3,4-c]pyridin-5-yl)-2-oxo-ethyl]-2-methyl-propionamide.
This invention also provides compounds of the formula 
or a stereoisomeric mixture thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomer thereof, or a prodrug of such compound, mixture or isomer thereof, or a pharmaceutically acceptable salt of the compound, mixture, isomer or prodrug,
wherein
HET is a heterocyclic moiety selected from the group consisting of 
d is 0, 1 or 2;
e is 1 or 2;
A is a divalent radical, where the left hand side of the radical as shown below is connected to Cxe2x80x3 and the right hand side of the radical as shown below is connected to Cxe2x80x2, selected from the group consisting of
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94S(O)2xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94C(O)xe2x80x94NR2,
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94C(O)xe2x80x94NR2xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR2xe2x80x94S(O)2xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94Oxe2x80x94C(O)xe2x80x94NR2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94NR12xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94N(R12)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94NR12xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94S(O)2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94NR2xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94S(O)2xe2x80x94,
xe2x80x94Oxe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94Oxe2x80x94,
xe2x80x94C(R9R10)xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94,
xe2x80x94C(O)xe2x80x94C(R9R10)xe2x80x94C(R9R10)xe2x80x94 and
xe2x80x94C(R9R10)xe2x80x94NR2xe2x80x94S(O)2xe2x80x94NR2xe2x80x94;
Q is a covalent bond or CH2;
W is CH or N;
X is CR9aR10a, Cxe2x95x90CH2 or Cxe2x95x90O;
Y is CR9R10, O or NR2;
Z is Cxe2x95x90O, Cxe2x95x90S or S(O)2;
R1 is hydrogen, xe2x80x94CN, xe2x80x94(CH2)qN(X6)C(O)X6, xe2x80x94(CH2)qN(X6)C(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2X6, xe2x80x94(CH2)qN(X6)C(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qC(O)OX6, xe2x80x94(CH2)qC(O)O(CH2)tA1, xe2x80x94(CH2)qOX6, xe2x80x94(CH2)qOC(O)X6, xe2x80x94(CH2)qOC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qOC(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qOC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)X6, xe2x80x94(CH2)qC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)OX6, xe2x80x94(CH2)qN(X6)S(O)2N(X6)(X6), xe2x80x94(CH2)qS(O)mX6, xe2x80x94(CH2)qS(O)m(CH2)txe2x80x94A1, xe2x80x94(C1-C10)alkyl, xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl, xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(C1-C6)alkyl, xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94A1 or xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94(C3-C7)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl or 1, 2 or 3 fluoro groups;
Y1 is O, S(O)m, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94Cxe2x89xa1CHxe2x80x94, xe2x80x94N(X6)C(O)xe2x80x94, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94OC(O)N(X)xe2x80x94 or xe2x80x94OC(O)xe2x80x94;
q is 1, 2, 3 or 4;
t is 0, 1, 2 or 3;
said (CH2)q group and (CH2)t group in the definition of R1 are optionally independently substituted with hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl, 1, 2 or 3 fluoro groups or 1 or 2 (C1-C4)alkyl groups;
R1A is selected from the group consisting of hydrogen, F, Cl, Br, I, (C1-C6)alkyl, phenyl(C1-C4)alkyl, pyridyl(C1-C3)alkyl, thiazolyl(C1-C3)alkyl and thienyl(C1-C3)alkyl, provided that R1A is not F, Cl, Br or I when a heteroatom is vicinal to Cxe2x80x3;
R2 is hydrogen, (C1-C8)alkyl, xe2x80x94(C0-C3)alkyl-(C3-C8)cycloalkyl, xe2x80x94(C1-C4)alkyl-A1 or A1;
where the alkyl groups and the cycloalkyl groups in the definition of R2 are optionally substituted with hydroxy, xe2x80x94C(O)OX6, xe2x80x94C(O)N(X6)(X6), xe2x80x94N(X6)(X6, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)A1, xe2x80x94C(O)(X6), CF3, CN or 1, 2 or 3 independently selected halo groups;
R3 is selected from the group consisting of A1, (C1-C10)alkyl, xe2x80x94(C1-C6)alkyl-A1, xe2x80x94(C1-C6)alkyl-(C3-C7)cycloalkyl, xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C1-C5)alkyl, xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C0-C5)alkyl-A1 and xe2x80x94(C1-C5)alkyl-X1xe2x80x94(C1-C5)alkyl-(C3-C7)cycloalkyl;
where the alkyl groups in the definition of R3 are optionally substituted with xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX3, 1, 2, 3, 4 or 5 independently selected halo groups or 1, 2 or 3 independently selected xe2x80x94OX3 groups;
X1 is O, S(O)m, xe2x80x94N(X2)C(O)xe2x80x94, xe2x80x94C(O)N(X2)xe2x80x94, xe2x80x94OC(O)xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94CX2xe2x95x90CX2xe2x80x94, xe2x80x94N(X2)C(O)Oxe2x80x94, xe2x80x94OC(O)N(X2)xe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94;
R4 is hydrogen, (C1-C6)alkyl or (C3-C7)cycloalkyl, or R4 is taken together with R3 and the carbon atom to which they are attached and form (C5-C7)cycloalkyl, (C5-C7)cycloalkenyl, a partially saturated or fully saturated 4- to 8-membered ring having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen, or is a bicyclic ring system consisting of a partially saturated or fully saturated 5- or 6-membered ring, fused to a partially saturated, fully unsaturated or fully saturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
X4 is hydrogen or (C1-C6)alkyl or X4 is taken together with R4 and the nitrogen atom to which X4 is attached and the carbon atom to which R4 is attached and form a five to seven membered ring;
R6 is a bond or is 
where a and b are each independently 0, 1, 2 or 3;
X5 and X5a are each independently selected from the group consisting of hydrogen, CF3, A1 and optionally substituted (C1-C5)alkyl;
the optionally substituted (C1-C6)alkyl in the definition of X5 and X5a is optionally substituted with a substituent selected from the group consisting of A1, OX2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX2, (C3-C7)cycloalkyl, xe2x80x94N(X2)(X2) and xe2x80x94C(O)N(X2)(X2);
or the carbon bearing X5 or X5a forms one or two alkylene bridges with the nitrogen atom bearing R7 and R8 wherein each alkylene bridge contains 1 to 5 carbon atoms, provided that when one alkylene bridge is formed then only one of X5 or X5a is on the carbon atom and only one of R7 or R8 is on the nitrogen atom and further provided that when two alkylene bridges are formed then X5 and X5a cannot be on the carbon atom and R7 and R8 cannot be on the nitrogen atom;
or X5 is taken together with X5a and the carbon atom to which they are attached and form a partially saturated or fully saturated 3- to 7-membered ring, or a partially saturated or fully saturated 4- to 8-membered ring having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen;
or X5 is taken together with X5a and the carbon atom to which they are attached and form a bicyclic ring system consisting of a partially saturated or fully saturated 5- or 6-membered ring, optionally having 1 or 2 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen, fused to a partially saturated, fully saturated or fully unsaturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
Z1 is a bond, O or Nxe2x80x94X2, provided that when a and b are both O then Z1 is not Nxe2x80x94X2 or O;
R7 and R8 are each independently hydrogen or optionally substituted (C1-C6)alkyl;
where the optionally substituted (C1-C6)alkyl in the definition of R7 and R8 is optionally independently substituted with A1, xe2x80x94C(O)Oxe2x80x94(C1-C6)alkyl, xe2x80x94S(O)m(C1-C6)alkyl, 1 to 5 halo groups, 1 to 3 hydroxy groups, 1 to 3 xe2x80x94Oxe2x80x94C(O)(C1-C10)alkyl groups or 1 to 3 (C1-C6)alkoxy groups; or
R7 and R8 can be taken together to form xe2x80x94(CH2)rxe2x80x94Lxe2x80x94(CH2)rxe2x80x94;
where L is C(X2)(X2), S(O)m or N(X2);
R9, R9a, R10 and R10a are each independently hydrogen, fluoro, hydroxy, (C1-C4)alkoxy or (C1-C5)alkyl optionally substituted with 1 to 5 halogroups, provided that at least one of R9, R9a, R10 or R10a is present and is (C1-C;4)alkoxy;
R11 is selected from the group consisting of (C1-C5)alkyl and phenyl optionally substituted with 1-3 substitutents each independently selected from the group consisting of (C1-C5)alkyl, halo and (C1-C5)alkoxy;
R12 is selected from the group consisting of (C1-C5)alkylsulfonyl, (C1-C5)alkanoyl and (C1-C5)alkyl where the alkyl portion is optionally independently substituted by 1-5 halo groups;
A1 for each occurrence is independently selected from the group consisting of (C5-C7)cycloalkenyl, phenyl, a partially saturated, fully saturated or fully unsaturated 4- to 8-membered ring optionally having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen and a bicyclic ring system consisting of a partially saturated, fully unsaturated or fully saturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen, fused to a partially saturated, fully saturated or fully unsaturated 5 or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
A1 for each occurrence is independently optionally substituted, on one or optionally both rings if A1 is a bicyclic ring system, with up to three substituents, each substituent independently selected from the group consisting of F, Cl, Br, I, OCF3, OCF2H, CF3, CH3, OCH3, xe2x80x94OX6, xe2x80x94C(O)N(X6)(X6), xe2x80x94C(O)OX6, oxo, (C1-C0)alkyl, nitro, cyano, benzyl, xe2x80x94S(O)m(C1-C6)alkyl, 1H-tetrazol-5-yl, phenyl, phenoxy, phenylalkyloxy, halophenyl, methylenedioxy, xe2x80x94N(X6)(X6), xe2x80x94N(X6)C(O)(X6), xe2x80x94S(O)2N(X6)(X6), xe2x80x94N(X6)S(O)2-phenyl, xe2x80x94N(X6)S(O)2X6, xe2x80x94CONX11X12, xe2x80x94S(O)2NX11X12, xe2x80x94NX6S(O)2X12, xe2x80x94NX6CONX11X12, xe2x80x94NX6S(O)2NX11X12, xe2x80x94NX6C(O)X12, imidazolyl, thiazolyl and tetrazolyl, provided that if A1 is optionally substituted with methylenedioxy then it can only be substituted with one methylenedioxy;
where X11 is hydrogen or optionally substituted (C1-C6)alkyl;
the optionally substituted (C1-C6)alkyl defined for X11 is optionally independently substituted with phenyl, phenoxy, (C1-C6)alkoxycarbonyl, xe2x80x94S(O)m(C1-C6)alkyl, 1 to 5 halo groups, 1 to 3 hydroxy groups, 1 to 3 (C1-C10)alkanoyloxy groups or 1 to 3 (C1-C6)alkoxy groups;
X12 is hydrogen, (C1-C6)alkyl, phenyl, thiazolyl, imidazolyl, furyl or thienyl, provided that when X12 is not hydrogen, the X12 group is optionally substituted with one to three substituents independently selected from the group consisting of Cl, F, CH3, OCH3, OCF3 and CF3;
or X11 and X12 are taken together to form xe2x80x94(CH2)rxe2x80x94L1(CH2)rxe2x80x94;
L1 is C(X2)(X2), O, S(O)m or N(X2);
r for each occurrence is independently 1, 2 or 3;
X2 for each occurrence is independently hydrogen, optionally substituted (C1-C6)alkyl or optionally substituted (C1-C7)cycloalkyl, where the optionally substituted (C1-C6)alkyl and optionally substituted (C1-C7)cycloalkyl in the definition of X2 are optionally independently substituted with xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)OX3, 1 to 5 halo groups or 1-3 OX3 groups;
X3 for each occurrence is independently hydrogen or (C1-C6)alkyl;
X6 for each occurrence is independently hydrogen, optionally substituted (C1-C6)alkyl, (C2-C6)halogenated alkyl, optionally substituted (C3-C7)cycloalkyl, (C3-C7)-halogenated cycloalkyl, where optionally substituted (C1-C6)alkyl and optionally substituted (C3-C7)cycloalkyl in the definition of X6 is optionally independently mono- or di-substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, CONH2, xe2x80x94S(O)m(C1-C6)alkyl, carboxylate (C1-C4)alkyl ester or 1H-tetrazol-5-yl; or
when there are two X6 groups on one atom and both X6 are independently (C1-C6)alkyl, the two (C1-C6)alkyl groups may be optionally joined and, together with the atom to which the two x6 groups are attached, form a 4- to 9-membered ring optionally having oxygen, sulfur or NX7 as a ring member;
X7 is hydrogen or (C1-C6)alkyl optionally substituted with hydroxy;
m for each occurrence is independently 0, 1 or 2;
with the proviso that:
X6 and X12 cannot be hydrogen when attached to C(O) or S(O)2 in the form C(O)X6, C(O)X12, S(O)2X6 or S(O)2X12; and
when R6 is a bond then L is N(X2) and each r in the definition xe2x80x94(CH2)rxe2x80x94Lxe2x80x94(CH2)rxe2x80x94 is independently 2 or 3.
A preferred group of compounds within the scope of the compounds disclosed in the immediately preceding paragraph, designated the ZA Group, comprises those compounds or a stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
HET is 
R1 is xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl or (C1-C10)alkyl;
where A1 in the definition or R1 is phenyl, pyridyl, thiazolyl or thienyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3;
the cycloalkyl and alkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy or 1 to 3 fluoro atoms;
q is 1 or 2;
t is 1 or 2;
R3 is selected form the group consisting of phenyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, phenyl-CH2xe2x80x94Sxe2x80x94CH2xe2x80x94, pyridyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, thienyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94 and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94; where the carbon atom bearing the substituent R3 is of the (R)-configuration;
where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3 
R4 is hydrogen;
R6 is 
xe2x80x83where Z1 is a bond; X5 and X5a are each methyl; a and b are each 0;
R7 and R8 or each hydrogen;
X4 is hydrogen.
A group of compounds which is preferred within the ZA Group of compounds, designated the ZB Group, comprises those compounds or stereoisomeric mixtures thereof, diastereomerically enriched, diastereomerically pure, enantiomerically enriched or enantiomerically pure isomers thereof, or prodrugs of such compounds, mixtures or isomers thereof, or pharmaceutically acceptable salts of the compounds, mixtures, isomers or prodrugs wherein:
Z is Cxe2x95x90O; Q is a covalent bond;
Y is CR9R10 
where R9 in the definition of Y is selected from the group consisting of hydrogen, fluoro, hydroxy, (C1-C2)alkoxy and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups; and R10 in the definition of Y is selected from the group consisting of hydrogen, fluoro, and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups with the proviso that R10 cannot be fluoro when R9 is hydroxy or (C1-C2)alkoxy;
and X is CHR9a 
where R9 in the definition of X is selected from the group consisting of hydrogen, fluoro, hydroxy, (C1-C2)alkoxy and (C1-C2)alkyl optionally substituted with 1-3 fluoro groups.
R1 is xe2x80x94CH2A1 
where A1 is phenyl, pyridyl or thiazolyl, optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3; and
R3 is selected form the group consisting of 3-indolyl-CH2xe2x80x94, phenyl-(CH2)3xe2x80x94, phenyl-CH2xe2x80x94Oxe2x80x94CH2and thiazolyl-CH2xe2x80x94Oxe2x80x94CH2xe2x80x94,
where the aryl portion of the groups defined for R3 is optionally substituted with one to three substituents, each substituent being independently selected from the group consisting of F, Cl, CH3, OCH3, OCF2H, OCF3 and CF3.
A group of compounds which is preferred within the ZB Group of compounds, designated the ZC Group, comprises those compounds or prodrugs of such compounds or pharmaceutically acceptable salts of the compounds or prodrugs where the compound is the 8(R,S),8a(R,S) diastereomeric mixture, the 8(R),8a(R) diastereomer, the 8(S),8a(S) diastereomer, the 8(R),8a(S) diastereomer, or the 8(S),8a(R) diastereomer of 2-amino-N-[1(R)-benzyloxymethyl-2-(8-methoxy-6-oxo-8a-pyridin-2-ylmethyl-hexahydro-pyrrolo[1 ,2-a]pyrazin-2-yl)-2-oxo-ethyl]-2-methyl-propionamide.
This invention also provides methods of treating or preventing sleep disorders in a mammal, including humans or other animals such as especially dogs, cats and horses, which comprise administereing to such human or other animal an effective amount of a compound of Formula I.
This invention also provides the L-tartrate salt of 2-amino-N-{1-(R)-benzyloxymethyl-2-[1,3dioxo-8a-(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl]-2-oxo-ethyl}-2-methyl-propionamide.
This invention also provides compounds of the formula 
where R1 is hydrogen, xe2x80x94CN, xe2x80x94(CH2)qN(X6)C(O)X6, xe2x80x94(CH2)qN(X6)C(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)S(O)2X6, xe2x80x94(CH2)qN(X6)C(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qC(O)OX6, xe2x80x94(CH2)qC(O)O(CH2)txe2x80x94A1, xe2x80x94(CH2)qOX6, xe2x80x94(CH2)qOC(O)X6, xe2x80x94(CH2)qOC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qOC(O)N(X6)(CH2)txe2x80x94A1, xe2x80x94(CH2)qOC(O)N(X6)(X6), xe2x80x94(CH2)qC(O)X6, xe2x80x94(CH2)qC(O)(CH2)txe2x80x94A1, xe2x80x94(CH2)qN(X6)C(O)OX6, xe2x80x94(CH2)qN(X6)S(O)2N(X6)(X6), xe2x80x94(CH2)qS(O)mX6, xe2x80x94(CH2)qS(O)m(CH2)txe2x80x94A1, xe2x80x94(C1-C10)alkyl, xe2x80x94(CH2)txe2x80x94A1, xe2x80x94(CH2)qxe2x80x94(C3-C7)cycloalkyl, xe2x80x94(CH2)qxe2x80x94Y1 xe2x80x94(C1xe2x80x94C6)alkyl, xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94A1 or xe2x80x94(CH2)qxe2x80x94Y1xe2x80x94(CH2)txe2x80x94(C3-C7)cycloalkyl;
where the alkyl and cycloalkyl groups in the definition of R1 are optionally substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl or 1, 2 or 3 fluoro groups;
Y1 is O, S(O)m, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94CHxe2x95x90CHxe2x80x94, xe2x80x94Cxe2x89xa1Cxe2x80x94, xe2x80x94N(X6)C(O)xe2x80x94, xe2x80x94C(O)NX6xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94OC(O)N(X6)xe2x80x94 or xe2x80x94OC(O)xe2x80x94;
m for each occurrence is 0, 1 or 2;
q is 0, 1, 2, 3 or 4;
t is 0, 1, 2 or 3;
said (CH2)q group and (CH2)t group in the definition of R1 are optionally independently substituted with hydroxy, (C1-C4)alkoxy, carboxyl, xe2x80x94CONH2, xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94CO2(C1-C4)alkyl ester, 1H-tetrazol-5-yl, 1, 2 or 3 fluoro groups or 1 or 2 (C1-C4)alkyl groups;
A1 for each occurrence is independently selected from the group consisting of (C5-C7)cycloalkenyl, phenyl, a partially saturated, fully saturated or fully unsaturated 4- to 8-membered ring optionally having 1 to 4 heteroatoms independently selected from the group consisting of oxygen, sulfur and nitrogen and a bicyclic ring system consisting of a partially saturated, fully unsaturated or fully saturated 5- or 6 membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen, fused to a partially saturated, fully saturated or fully unsaturated 5- or 6-membered ring, optionally having 1 to 4 heteroatoms independently selected from the group consisting of nitrogen, sulfur and oxygen;
A1 for each occurrence is independently optionally substituted, on one or optionally both rings if A1 is a bicyclic ring system, with up to three substituents, each substituent independently selected from the group consisting of F, Cl, Br, I, OCF3, OCF2H, CF3, CH3, OCH3, xe2x80x94OX6, xe2x80x94C(O)N(X6)(X6), xe2x80x94C(O)OX6, oxo, (C1-C6)alkyl, nitro, cyano, benzyl, xe2x80x94S(O)m(C1-C6)alkyl, 1H-tetrazol-5yl, phenyl, phenoxy, phenylalkyloxy, halophenyl, methylenedioxy, xe2x80x94N(X6)(X6), xe2x80x94N(X6)C(O)(X6), xe2x80x94S(O)2N(X6)(X6), xe2x80x94N(X6)S(O)2-phenyl, xe2x80x94N(X6)S(O)2X6, xe2x80x94CONX11X12, xe2x80x94S(O)2NX11X12, xe2x80x94NX6S(O)2X12, xe2x80x94NX6CONX11X12, xe2x80x94NX6S(O)2NX11X12, xe2x80x94NX6C(O)X12, imidazolyl, thiazolyl and tetrazolyl, provided that if A1 is optionally substituted with methylenedioxy then it can only be substituted with one methylenedioxy;
where X11 is hydrogen or optionally substituted (C1-C6)alkyl;
the optionally substituted (C1-C6)alkyl defined for X11 is optionally independently substituted with phenyl, phenoxy, (C1-C6)alkoxycarbonyl, xe2x80x94S(O)m(C1-C6)alkyl, 1 to 5 halo groups, 1 to 3 hydroxy groups, 1 to 3 (C1-C10)alkanoyloxy groups or 1 to 3 (C1-C6)alkoxy groups;
X12 is hydrogen, (C1-C6)alkyl, phenyl, thiazolyl, imidazolyl, furyl or thienyl, provided that when X12 is not hydrogen, the X12 group is optionally substituted with one to three substituents independently selected from the group consisting of Cl, F, CH3, OCH3, OCF3 and CF3;
or X11 and X12 are taken together to form xe2x80x94(CH2)rxe2x80x94L1xe2x80x94(CH2)rxe2x80x94;
L1 is C(X2)(X2), O, S(O)m or N(X2);
X for each occurrence is independently hydrogen, optionally substituted (C1-C6)alkyl, (C2-C6)halogenated alkyl, optionally substituted (C3-C7)cycloalkyl, (C3-C7)-halogenated cycloalkyl, where optionally substituted (C1-C6)alkyl and optionally substituted (C3-C7)cycloalkyl in the definition of X6 is optionally independently mono or di-substituted with (C1-C4)alkyl, hydroxy, (C1-C4)alkoxy, carboxyl, CONH2,
S(O)m(C1-C6)alkyl, carboxylate (C1-C4)alkyl ester or 1H-tetrazol-5-yl; or
when there are two X6 groups on one atom and both X6 are independently (C1-C6)alkyl, the two (C1-C6)alkyl groups may be optionally joined and, together with the atom to which the two X6 groups are attached, form a 4- to 9-membered ring optionally having oxygen, sulfur or NX7 as a ring member, and
R2 is hydrogen, (C1-C8)alkyl, xe2x80x94(C0-C3)alkyl-(C3-C8)cycloalkyl, xe2x80x94(C1-C4)alkyl-A1 or A1;
where the alkyl groups and the cycloalkyl groups in the definition of R2 are optionally substituted with hydroxy, xe2x80x94C(O)OX6, xe2x80x94C(O)N(X6)(X6), xe2x80x94N(X6)(X6), xe2x80x94S(O)m(C1-C6)alkyl, xe2x80x94C(O)A1, xe2x80x94C(O)(X6), CF3, CN or 1, 2 or 3 independently selected halo groups.
A group of compounds which is preferred within the compounds disclosed within the immediately preceding paragraph, designated the XA Group, comprises those compounds wherein R1 is CH2xe2x80x94A1 and R2 is CF3CH2xe2x80x94.
A group of compounds which is preferred within the XA Group of 30 compounds, designated the XB Group, comprises those compounds wherein A1 is 2-pyridyl.
A compound which is preferred within the XB Group of compounds is 8a-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-tetrahydro-imidazo[1,5a]pyrazine-1,3-dione.
Another compound which is preferred within the XB group of compounds is the L-tartrate salt of 8a-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-tetrahydro-imidazo[1,5-a]pyrazine-1,3-dione.
This invention also provides a process for preparing 1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazine-7-carboxylic acid tert-butyl ester comprising reacting 8a-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-tetrahydro-imidazo[1,5-a]pyrazine-1,3-dione with D-tartaric acid in a reaction inert solvent at 0xc2x0 C. to about room temperature for about 5 minutes to about 48 hours.
This invention also provides a process for preparing 2-amino-N-(1(R)-benzyloxymethyl-2-(1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-methyl-propionamide hydrochloride comprising
(a) reacting 8a-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-tetrahydro-imidazo[1,5a]pyrazine-1,3-dione with D-tartaric acid in a reaction inert solvent to form 1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5a]pyrazine-7-carboxylic acid tert-butyl ester;
(b) reacting said 1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5a]pyrazine-7-carboxylic acid tert-butyl ester with 3-benzyloxy-2-(2-tert-butoxycarbonylamino-2-methyl-propionylamino)-propionic acid in the presence of a tertiary amine and 1-propanephosphonic acid cyclic anhydride in a reaction inert solvent to form (1-(1(R)-benzyloxymethyl-2-(1,3dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-oxo-ethylcarbamoyl)-1-methyl-ethyl)-carbamic acid tert-butyl ester; and
(c) reacting said (1-(1(R)-benzyloxymethyl-2-(1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5a]pyrazin-7-yl)-2-oxo-ethylcarbamoyl)-1-methyl-ethyl)-carbamic acid tert-butyl ester with concentrated hydrochloric acid in a reaction inert solvent to form 2-amino-N-(1(R)-benzyloxymethyl-2-(1,3-dioxo-8a(S)-pyridin-2-ylmethyl-2-(2,2,2-trifluoro-ethyl)-hexahydro-imidazo[1,5-a]pyrazin-7-yl)-2-methyl-propionamide hydrochloride.
In general the compounds of Formula I can be made by processes known in the chemical arts. Certain processes for the manufacture of Formula I compounds are provided as further features of the invention and are illustrated by the following reaction schemes.
In the above structural formulae and throughout the instant application, the following terms have the indicated meanings unless expressly stated otherwise:
The alkyl groups are intended to include, those alkyl groups of the designated length in either a straight or branched configuration which may optionally contain double or triple bonds. Exemplary of such alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tertiary butyl, pentyl, isopentyl, hexyl, isohexyl, allyl, ethynyl, propenyl, butadienyl, hexenyl and the like.
When the definition C0-alkyl occurs in the definition, it means a single covalent bond.
The alkoxy groups specified above are intended to include those alkoxy groups of the designated length in either a straight or branched configuration which may optionally contain double or triple bonds. Exemplary of such alkoxy groups are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tertiary butoxy, pentoxy, isopentoxy, hexoxy, isohexoxy, allyloxy, 2-propynyloxy, isobutenyloxy, hexenyloxy and the like.
The term xe2x80x9chalogenxe2x80x9d or xe2x80x9chaloxe2x80x9d is intended to include the halogen atoms fluorine, chlorine, bromine and iodine.
The term xe2x80x9chalogenated alkylxe2x80x9d is intended to include an alkyl group as defined hereinabove substituted by one or more halogen atoms as defined hereinabove.
The term xe2x80x9chalogenated cycloalkylxe2x80x9d is intended to include a cycloalkyl group substituted by one or more halogen atoms as defined hereinabove.
The term xe2x80x9carylxe2x80x9d is intended to include phenyl and naphthyl and aromatic 5- and 6-membered rings with 1 to 4 heteroatoms or fused 5- and/or 6-membered bicyclic rings with 1 to 4 heteroatoms of nitrogen, sulfur or oxygen. Examples of such heterocyclic aromatic rings are pyridine, thiophene (also known as thienyl), furan, benzothiophene, tetrazole, indole, N-methylindole, dihydroindole, indazole, N-formylindole, benzimidazole, thiazole, pyrimidine, and thiadiazole.
The expression xe2x80x9cprodrugxe2x80x9d refers to compounds that are drug precursors which following administration, release the drug in vivo via some chemical or physiological process (e.g., a prodrug on being brought to the physiological pH is converted to the desired drug form). Exemplary prodrugs upon cleavage release the corresponding free acid, and such hydrolyzable ester-forming residues of the compounds of this invention include but are not limited to carboxylic acid substituents (e.g., when R1 is xe2x80x94(CH2)qC(O)OX6 where X6 is hydrogen, or when R2 or A1 contains carboxylic acid) wherein the free hydrogen is replaced by (C1-C4)alkyl, (C2-C12)alkanoyloxymethyl, (C4-C9)1-(alkanoyloxy)ethyl, 1-methyl-1-(alkanoyloxy)-ethyl having from 5 to 10 carbon atoms, alkoxycarbonyloxymethyl having from 3 to 6 carbon atoms, 1-(alkoxycarbonyloxy)ethyl having from 4 to 7 carbon atoms, 1-methyl-1-(alkoxycarbonyloxy)ethyl having from 5 to 8 carbon atoms, N-(alkoxycarbonyl)aminomethyl having from 3 to 9 carbon atoms, 1-(N-(alkoxycarbonyl)amino)ethyl having from 4 to 10 carbon atoms, 3-phthalidyl, 4-crotonolactonyl, gamma-butyrolacton-4-yl, di-N,N-(C1-C2)alkylamino(-C2-C3)alkyl (such as xcex2-dimethylaminoethyl), carbamoyl-(C1-C2)alkyl, N,N-di(C1-C2)-alkylcarbamoyl-(C1-C2)alkyl and piperidino-, pyrrolidino- or morpholino(C2-C3)alkyl.
Other exemplary prodrugs release an alcohol of Formula I wherein the free hydrogen of the hydroxyl substituent (e.g., when R1 contains hydroxyl) is replaced by (C1-C6)alkanoyloxymethyl, 1-((C1-C6)alkanoyloxy)ethyl, 1-methyl-1-((C1-C6)alka-noyloxy)ethyl, (C1-C6)alkoxycarbonyloxymethyl, N-(C1-C6)alkoxy-carbonylamino-methyl, succinoyl, (C1-C6)alkanoyl, xcex1-amino(C1-C4)alkanoyl, arylacetyl and xcex1-aminoacyl, or xcex1-aminoacyl-xcex1-aminoacyl wherein said xcex1-aminoacyl moieties are independently any of the naturally occurring L-amino acids found in proteins, xe2x80x94P(O)(OH)2, xe2x80x94P(O)(O(C1-C6)alkyl)2 or glycosyl (the radical resulting from detachment of the hydroxyl of the hemiacetal of a carbohydrate).
Prodrugs of this invention where a carboxyl group in a carboxylic acid of Formula I is replaced by an ester may be prepared by combining the carboxylic acid with the appropriate alkyl halide in the presence of a base such as potassium carbonate in an inert solvent such as DMF at a temperature of about 0xc2x0 C. to 100xc2x0 C. for about 1 to about 24 hours. Alternatively, the acid is combined with the appropriate alcohol as solvent in the presence of a catalytic amount of acid such as concentrated sulfuric acid at a temperature of about 20xc2x0 C. to 120xc2x0 C., preferably at reflux, for about 1 hour to about 24 hours. Another method is the reaction of the acid in an inert solvent such as THF, with concomitant removal of the water being produced by physical (e.g., Dean Stark trap) or chemical (e.g., molecular sieves) means.
Prodrugs of this invention where an alcohol function has been derivatized as an ether may be prepared by combining the alcohol with the appropriate alkyl bromide or iodide in the presence of a base such as potassium carbonate in an inert solvent such as DMF at a temperature of about 0xc2x0 C. to 100xc2x0 C. for about 1 to about 24 hours. Alkanoylaminomethyl ethers may be obtained by reaction of the alcohol with a bis-(alkanoylamino)methane in the presence of a catalytic amount of acid in an inert solvent such as THF, according to a method described in U.S. Pat. No. 4,997,984. Alternatively, these compounds may be prepared by the methods described by Hoffman et al. in J. Org. Chem. 1994, 59, p. 3530.
Certain of the above defined terms may occur more than once in the above formula and upon such occurrence each term shall be defined independently of the other.
The compounds of the instant invention all have at least one asymmetric center as noted by the asterisk in the structural Formula I. Additional asymmetric centers may be present on the molecule depending upon the nature of the various substituents on the molecule. Each such asymmetric center will produce two optical isomers and it is intended that all such optical isomers, as separated, pure or partially purified optical isomers, racemic mixtures or diastereomeric mixtures thereof, be included within the scope of the instant invention. In the case of the asymmetric center represented by the asterisk, it has been found that the absolute stereochemistry of the more active and thus more preferred isomer is shown in Formula IA. This preferred absolute configuration also applies to Formula I. 
With the R4 substituent as hydrogen, the spatial configuration of the asymmetric center corresponds to that in a D-amino acid. In most cases this is also designated an R-configuration although this will vary according to the values of R3 and R4 used in making R- or S-stereochemical assignments.
The instant compounds are generally isolated in the form of their pharmaceutically acceptable acid addition salts, such as the salts derived from using inorganic and organic acids. Examples of such acids are hydrochloric, nitric, sulfuric, phosphoric, formic, acetic, trifluoroacetic, propionic, maleic, succinic, D-tartaric, L-tartaric, malonic, methane sulfonic and the like. In addition, certain compounds containing an acidic function such as a carboxy can be isolated in the form of their inorganic salt in which the counter-ion can be selected from sodium, potassium, lithium, calcium, magnesium and the like, as well as from organic bases.
The pharmaceutically acceptable salts are formed by taking about 1 equivalent of a compound of Formula I and contacting it with about 1 equivalent of the appropriate corresponding acid of the salt which is desired. Work-up and isolation of the resulting salt is well-known to those of ordinary skill in the art.
The growth hormone releasing compounds of Formula I are useful in vitro as unique tools for understanding how growth hormone secretion is regulated at the pituitary level. This includes use in the evaluation of many factors thought or known to influence growth hormone secretion such as age, sex, nutritional factors, glucose, amino acids, fatty acids, as well as fasting and non-fasting states. In addition, the compounds of this invention can be used in the evaluation of how other hormones modify growth hormone releasing activity. For example, it has already been established that somatostatin inhibits growth hormone release.
The compounds of Formula I can be administered to animals, including humans, to release growth hormone in vivo. The compounds are useful for treating symptoms related to GH deficiency; stimulating pre- and post-natal growth or enhancing feed efficiency and improving carcass quality of animals raised for meat production; increasing milk production in dairy cattle; improving estrous synchronization in livestock such as swine, beef and dairy cattle; improving bone or wound healing and improving vital organ function in animals. The compounds of the present invention, by inducing endogenous GH secretion, will alter body composition and modify other GH-dependent metabolic, immunologic or developmental processes. For example, the compounds of the present invention can be given to chickens, turkeys, livestock animals (such as sheep, pigs, horses, cattle, etc.) and companion animals (e.g., dogs). These compounds may also have utility in aquaculture to accelerate growth and improve the percent lean meat. In addition, these compounds can be administered to humans in vivo as a diagnostic tool to directly determine whether the pituitary is capable of releasing growth hormone. For example, the compounds of Formula I or a pharmaceutically acceptable salt or prodrug thereof can be administered in vivo to children and serum samples taken before and after such administration can be assayed for growth hormone. Comparison of the amounts of growth hormone in each of these samples would be a means for directly determining the ability of the patients pituitary to release growth hormone.
Accordingly, the present invention includes within its scope pharmaceutical compositions comprising, as an active ingredient, at least one of the compounds of Formula I or a pharmaceutically acceptable salt or prodrug thereof in association with a pharmaceutically acceptable carrier. Optionally, the pharmaceutical compositions can further comprise an anabolic agent in addition to at least one of the compounds of Formula I or a pharmaceutically acceptable salt or prodrug thereof, or another compound which exhibits a different activity, e.g., an antibiotic or coccidiostat (e.g., monensin) growth promotant or an agent to treat osteoporosis or with other pharmaceutically active materials wherein the combination enhances efficacy and minimizes side effects.
Growth promoting and anabolic agents include, but are not limited to, TRH, PTH, diethylstilbesterol, estrogens, B-agonists, theophylline, anabolic steroids, enkephalins, E series prostaglandins, compounds disclosed in U.S. Pat. No. 3,239,345, the disclosure of which is hereby incorporated by reference, e.g., zeranol; compounds disclosed in U.S. Pat. No. 4,036,979, the disclosure of which is hereby incorporated by reference, e.g., sulbenox; and peptides disclosed in U.S. Pat. No. 4,411,890, the disclosure of which is hereby incorporated by reference.
The growth hormone secretagogues of this invention in combination with other growth hormone secretagogues such as the growth hormone releasing peptides GHRP6 and GHRP-1 as described in U.S. Pat. No. 4,411,890, the disclosure of which is hereby incorporated by reference, and publications WO 89/07110, WO 89/07111 and B-HT920 as well as hexarelin and the newly discovered GHRP-2 as described in WO 93/04081 or growth hormone releasing hormone (GHRH, also designated GRF) and its analogs or growth hormone and its analogs or somatomedins including IGF-1 and IGF-2 or alpha-2-adrenergic agonists such as clonidine, xylazine, detomidine and medetomidine or serotonin 5HTID agonists such as sumitriptan or agents which inhibit somatostatin or its release such as physostigmine and pyridostigmine, are useful for increasing the endogenous levels of GH in mammals. The combination of a GH secretagogue of this invention with GRF results in synergistic increases of endogenous growth hormone.
As is well known to those skilled in the art, the known and potential uses of growth hormone are varied and multitudinous [See xe2x80x9cHuman Growth Hormonexe2x80x9d, Strobel and Thomas, Pharmacological Reviews, 46, pg. 1-34 (1994); T. Rosen et al., Horm Res, 1995; 43: pp. 93-99; M. Degerblad et al., European Journal of Endocrinology, 1995, 133: pp.180-188; J. O. Jorgensen, European Journal of Endocrinology, 1994, 130: pp. 224-228; K. C. Copeland et al., Journal of Clinical Endocrinology and Metabolism, Vol. 78 No. 5, pp. 1040-1047; J. A. Aloi et al., Journal of Clinical Endocrinology and Metabolism, Vol. 79 No. 4, pp. 943-949; F. Cordido et al., Metab. Clin. Exp., (1995), 44(6), pp. 745-748; K. M. Fairhall et al., J. Endocrinol., (1995), 145(3), pp. 417-426; R. M. Frieboes et al., Neuroendocrinology, (1995), 61(5), pp. 584-589; and M. Llovera et al., Int. J. Cancer, (1995), 61(1), pp. 138-141]. Thus, the administration of the compounds of this invention for purposes of stimulating the release of endogenous growth hormone can have the same effects or uses as growth hormone itself. These varied uses of growth hormone may be summarized as follows: stimulating growth hormone release in elderly humans or companion animals especially dogs, cats, camels and horses; treating growth hormone deficient adult humans or other animals especially dogs, cats, camels and horses; preventing catabolic side effects of glucocorticoids, treating osteoporosis, stimulating the immune system, accelerating wound healing, accelerating bone fracture repair, treating growth retardation, treating congestive heart failure as disclosed in PCT publications WO 95/28173 and WO 95/28174 (an example of a method for assaying growth hormone secretagogues for efficacy in treating congestive heart failure is disclosed in R. Yang et al., Circulation, Vol. 92, No. 2, p.262, 1995), treating acute or chronic renal failure or insufficiency; treating physiological short stature including growth hormone deficient children, treating short stature associated with chronic illness, treating obesity, treating growth retardation associated with Prader-Willi syndrome and Tumer""s syndrome; accelerating the recovery and reducing hospitalization of bum patients or following major surgery such as gastrointestinal surgery; treating intrauterine growth retardation, skeletal dysplasia, hypercortisonism and Cushings syndrome; replacing growth hormone in stressed patients; treating osteochondrodysplasias, Noonans syndrome, sleep disorders, Alzheimee""s disease, delayed wound healing, and psychosocial deprivation; treating pulmonary dysfunction and ventilator dependency; attenuating protein catabolic response after a major operation; treating malabsorption syndromes, reducing cachexia and protein loss due to chronic illness such as cancer or AIDS; accelerating weight gain and protein accretion in patients on TPN (total parenteral nutrition); treating hyperinsulinemia including nesidioblastosis; adjuvant treatment for ovulation induction and to prevent and treat gastric and duodenal ulcers; stimulating thymic development and preventing age-related decline of thymic function; adjunctive therapy for patients on chronic hemodialysis; treating immunosuppressed patients and enhancing antibody response following vaccination; improving muscle strength, increasing muscle mass, mobility, maintenance of skin thickness, metabolic homeostasis, renal hemeostasis in the frail elderly; stimulating osteoblasts, bone remodeling, and cartilage growth; treating neurological diseases such as peripheral and drug induced neuropathy, Guillian-Barre Syndrome, amyotrophic lateral sclerosis, multiple sclerosis, cerebrovascular accidents and demyelinating diseases; and stimulating wool growth in sheep.
Uses of GH in farm animals raised for meat production such as chickens, turkeys, sheep, pigs and cattle include stimulation of pre- and post-natal growth, enhanced feed efficiency in animals raised for meat production, improved carcass quality (increased muscle to fat ratio) (Campbell, R. G. et al., (1989), J. Anim. Sci. 67, 1265; Dave, D. J., Bane, D. P., (1990), The Compendium Food Anual, Vol. 12(1), 117; Holden, P. J., (1990), Agri-Practice, 11(3), 25; Claus, R., Weiber, U., (1994), Livestock Production Science, 37, 245; Roeder, R. et al., (1994), Growth Regulation, 4, 101); increased milk production in dairy cattle (McBride, B. W. et al., (1988), Research and Development in Agriculture 5(1), 1; McDowell, G. H. et al., (1988), Aust. J. Biol. Sci., 41, 279); improved body composition; modification of other GH-dependent metabolic (Claus, R. and Weiber, U., (1994), Livestock Production Science, 37, 245) and immunologic functions such as enhancing antibody response following vaccination or improved developmental processes; and may have utility in aquaculture to accelerate growth and improve the protein-to-fat ratio in fish.
Preferred uses in companion animals include stimulating endogenous growth hormone release in companion animals such as dogs, cats and horses; treating disorders of aging (Detenbeck, L. C., Jowsey, J., Clinical Orthopedics and Related Research, July-August 1969, No. 65, pp. 76-80); stimulating thymic development and preventing agerelated decline of thymic function (Goff, B. L. et al., Clinical and Experimental Immunology, 1987, 68:3, pp. 580-587; Morrison, W. B. et al., Am. J. Vet. Res., Jan. 1990, 51:1, pp. 65-70; Roth, J. A. et al., Am. J. Vet. Res., 1984, Vol. 45, pp. 1151-1155); preventing age-related decline of thymic function; preventing age-related decline in cognition; accelerating wound healing (Jacks, T. et al., Vet. Surg. 1996, 25, (5), 430); accelerating bone fracture repair (Pandey, S. K, Udupa, K. N., Indian J. Vet. Surg. 1 (2): 7378, July 1980); stimulating osteoblasts, bone remodelling and cartilage growth (Harris, W. H. et al., Calc. Tiss. Res., 10, 1972, pp. 1-13; Heaney, R. P. et al., Calc. Tiss. Res. 10, 1972, pp. 14-22; Mankin. H. J. et al., J. of Bone and Joint Surgery, Vol. 60-A, #8, December 1978, pp. 1071-1075); attenuating protein catabolic response after major surgery, accelerating recovery from bum injuries and major surgeries such as gastrointestinal surgery; stimulating the immune system and enhancing antibody response following vaccination; treating congestive heart failure, treating acute or chronic renal failure or insufficiency, treating obesity; treating growth retardation, skeletal dysplasia and osteochondrodysplasias; preventing catabolic side effects of glucocorticoids; treating Cushing""s syndrome; treating malabsorption syndromes, reducing cachexia and protein loss due to chronic illness such as cancer; accelerating weight gain and protein accretion in animals receiving total parenteral nutrition; providing adjuvant treatment for ovulation induction and to prevent gastrointestinal ulcers; improving muscle mass, strength and mobility; maintenance of skin thickness, and improving vital organ function and metabolic homeostasis.
The growth hormone secretagogues of this invention, compounds of Formula I, or a pharmaceutically acceptable salt or prodrug thereof in combination with an alpha-2 adrenergic agonist are useful in promoting GH secretion in humans and other animals (See Cella, S. G. et al., Acta Endocrinologica (Copenh.) 1989, 121, pp. 177-184). As such, a combination of a compound of Formula I or a pharmaceutically acceptable salt or prodrug thereof and an alpha-2 adrenergic agonist is useful in the treatment or prevention of frailty associated with aging, congestive heart failure and obesity which comprises administering to a human or another animal, especially dogs, cats and horses, in need of such treatment a combination of an alpha-2 adrenergic agonist and a compound of Formula I or a pharmaceutically acceptable salt or prodrug thereof, defined above. Preferred alpha-2 adrenergic agonists include clonidine, which is disclosed in U.S. Pat. No. 3,202,660 the disclosure of which is hereby incorporated by reference, xylazine, which is disclosed in U.S. Pat. No. 3,235,550 the disclosure of which is hereby incorporated by reference and medetomidine, which is disclosed in U.S. Pat. No. 4,544,664 the disclosure of which is hereby incorporated by reference. In another aspect, this invention provides methods for accelerating bone fracture repair and wound healing, attenuating protein catabolic response after a major operation, and reducing cachexia and protein loss due to chronic illness, which comprise administering to a human or another animal, especially dogs, cats and horses in need of such treatment a combination of an alpha-2 adrenergic agonist such as clonidine, xylazine or medetomidine and a compound of Formula I or a pharmaceutically acceptable salt or prodrug thereof. It has been shown that alpha-2 adrenergic agonists cause release of endogenous growth hormone in human and canine subjects (Celia et al., Life Sciences (1984), 34:447-454; Hampshire J, Altszuler N., American Journal of Veterinary Research (1981), 42:6, 1073-1076; Valcavi et al., Clinical Endocrinology (1988), 29:309-316; Morrison et al., American Journal of Veterinary Research (1990), 51:1, 65-70;), and that the co-administration of an alpha-2 adrenergic agonist with growth hormone-releasing factor restores defective growth hormone secretion in aged dogs (Arce et al., Brain Research (1990), 537:359-362; Celia et al., Neuroendocrinology (1993), 57:432-438).
This invention also relates to a method of treating insulin resistant conditions such as Non-Insulin Dependent Diabetes Mellitus (NIDDM) and reduced glycemic control associated with obesity and aging in a mammal in need thereof which comprises administering to said mammal an effective amount of a compound of the Formula I or a pharmaceutically acceptable salt or prodrug thereof.
This invention is directed to the use of growth hormone secretagogues specifically growth hormone releasing peptides (GHRP) or GHRP mimetics of Formula I or a pharmaceutically acceptable salt or prodrug thereof to improve glycemic control. Agents that increase growth hormone (GH) levels would not be expected to have this effect since it is widely recognized that GH is diabetogenic in animals and in humans. In acromegalics, glucose utilization and suppression of hepatic glucose production are impaired (see Hansen, I., et al., Am J Physiol, 250:E269 (1986)). In this disease of GH excess, impaired glucose handling and hyperinsulinemia have been reversed by pituitary surgery or chemotherapy which reduced GH levels (see Levin S. R., et al., Am J Med, 57:526 (1974), Feek, C. M., et al., J Clin Endocrinol 22:532 (1981)). Furthermore, administration of GH to older subjects caused hyperglycemia, glucose intolerance and hyperinsulinemia in numerous studies (see Aloia, J. F., et al., J Clin Endocrinol Metab, 43:992 (1976); Binnerts et al., J Clin Endocrinol Metab, 67:1312 (1988); Marcus, R., et al., J Clin Endocrinol Metab, 70:519 (1990)). Therefore, GH therapy is contra-indicated for individuals with diabetes or those at risk for diabetes.
It will be known to those skilled in the art that there are numerous compounds now being used in an effort to treat the diseases or therapeutic indications enumerated above. Combinations of these therapeutic agents, some of which have also been mentioned above, with growth promotant exhibit anabolic and desirable properties of these various therapeutic agents. In these combinations, the therapeutic agents and the growth hormone secretagogues of this invention may be independently and sequentially administered in any order or coadministered in dose ranges from one one-hundredth to one times the dose levels which are effective when these compounds and secretagogues are used singly. Combined therapy to inhibit bone resorption, prevent osteoporosis, reduce skeletal fracture, enhance the healing of bone fractures, stimulate bone formation and increase bone mineral density can be effectuated by combinations of bisphosphonates and the growth hormone secretagogues of this invention. See PCT publication WO 95/11029 for a discussion of combination therapy using bisphosphonates and GH secretagogues. The use of bisphosphonates for these utilities has been reviewed, for example, by Hamdy, N. A. T., Role of Bisphosphonates in Metabolic Bone Diseases, Trends in Endocrinol. Metab., 1993, 4, pages 19-25. Bisphosphonates with these utilities include but are not limited to alendronate, tiludronate, dimethyl-APD, risedronate, etidronate, YM-175, clodronate, pamidronate, and BM-210995 (ibandronate). According to their potency, oral daily dosage levels of the bisphosphonate of between 0.1 mg/kg and 5 g/kg of body weight and daily dosage levels of the growth hormone secretagogues of this invention of between 0.01 mg/kg to 20 mg/kg of body weight are administered to patients to obtain effective treatment of osteoporosis.
The compounds of this invention may be combined with a mammalian estrogen agonist/antagonist. Any estrogen agonist/antagonist may be used as the second compound of this invention. The term estrogen agonist/antagonist refers to compounds which bind with the estrogen receptor, inhibit bone turnover and prevent bone loss. In particular, estrogen agonists are herein defined as chemical compounds capable of binding to the estrogen receptor sites in mammalian tissue, and mimicking the actions of estrogen in one or more tissue. Estrogen antagonists are herein defined as chemical compounds capable of binding to the estrogen receptor sites in mammalian tissue, and blocking the actions of estrogen in one or more tissues. Such activities are readily determined by those skilled in the art according to standard assays including estrogen receptor binding assays, standard bone histomorphometric and densitometer methods (see Eriksen E. F. et al., Bone Histomorphometry, Raven Press, New York, 1994, pages 1-74; Grier S. J. et al., The Use of Dual-Energy X-Ray Absorptiometry In Animals, Inv. Radiol., 1996, 31(1):50-62; Wahner H. W. and Fogelman I., The Evaluation of Osteoporosis: Dual Energy X-Ray Absorptiometry in Clinical Practice., Martin Dunitz Ltd., London 1994, pages 1-296). A variety of these compounds are described and referenced below, however, other estrogen agonists/antagonists will be known to those skilled in the art. A preferred estrogen agonist/antagonist is droloxifene: (phenol, 3-[1-[4[2-(dimethylamino)ethoxy]-phenyl]-2-phenyl-1-butenyl]-, (E)-) and associated compounds which are disclosed in U.S. Pat. No. 5,047,431, the disclosure of which is hereby incorporated by reference.
Another preferred estrogen agonist/antagonist is tamoxifen: (ethanamine,2-[4-(1,2-diphenyl-1-butenyl)phenoxy]-N,N-dimethyl, (Z)-2,2-hydroxy-1,2,3-propanetri-carboxylate (1:1)) and associated compounds which are disclosed in U.S. Pat. No. 4,536,516, the disclosure of which is hereby incorporated by reference. Another related compound is 4-hydroxy tamoxifen which is disclosed in U.S. Pat. No. 4,623,660, the disclosure of which is hereby incorporated by reference.
Another preferred estrogen agonist/antagonist is raloxifene: (methanone, [6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thien-3-yl][4-[2-(1-piperidinyl)ethoxy]phenyl]-hydrochloride) and associated compounds which are disclosed in U.S. Pat. No. 4,418,068, the disclosure of which is hereby incorporated by reference.
Another preferred estrogen agonist/antagonist is idoxifene: Pyrrolidine, 1-[[4-[[1-(4-iodophenyl)-2-phenyl-1-Butenyl]phenoxy]ethyl] and associated compounds which are disclosed in U.S. Pat. No. 4,839,155, the disclosure of which is hereby incorporated by reference.
Other preferred estrogen agonist/antagonists include compounds as described in commonly assigned U.S. Pat. No. 5,552,412 the disclosure of which is hereby incorporated by reference. Especially preferred compounds which are described therein are:
cis-6-(4-fluoro-phenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
(xe2x88x92)-cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
cis-1-[6xe2x80x2-pyrrolodinoethoxy-3xe2x80x2-pyridyl]-2-phenyl-6-hydroxy-1,2,3,4-tetrahydronaphthalene;
1-(4xe2x80x2-pyrrolidinoethoxyphenyl)-2-(4xe2x80x3-fluorophenyl)-6-hydroxy-1,2,3,4-tetrahydroisoquinoline;
cis-6-(4-hydroxyphenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; and
1-(4xe2x80x2-pyrrolidinolethoxyphenyl)-2-phenyl-6-hydroxy-1,2,3,4-tetrahydroisoquinoline.
Other estrogen agonist/antagonists are described in U.S. Pat. No. 4,133,814, the disclosure of which is hereby incorporated by reference. U.S. Pat. No. 4,133,814 discloses derivatives of 2-phenyl-3-aroyl-benzothiophene and 2-phenyl-3-aroylbenzothiophene-1-oxide.
The following paragraphs provide preferred dosage ranges for various anti-resorptive agents.
The amount of the anti-resorptive agent to be used is determined by its activity as a bone loss inhibiting agent. This activity is determined by means of an individual compound""s pharmacokinetics and its minimal maximal effective dose in inhibition of bone loss using a protocol such as those referenced above.
In general an effective dosage for the activities of this invention, for example the treatment of osteoporosis, for the estrogen agonists/antagonists (when used in combination with a compound of Formula I or a pharmaceutically acceptable salt or prodrug thereof of this invention) is in the range of 0.01 to 200 mg/kg/day, preferably 0.5 to 100 mg/kg/day.
In particular, an effective dosage for droloxifene is in the range of 0.1 to 40 mg/kg/day, preferably 0.1 to 5 mg/kg/day.
In particular, an effective dosage for raloxifene is in the range of 0.1 to 100 mg/kg/day, preferably 0.1 to 10 mg/kg/day.
In particular, an effective dosage for tamoxifen is in the range of 0.1 to 100 mg/kg/day, preferably 0.1 to 5 mg/kg/day.
In particular, an effective dosage for
cis-6-(4-fluoro-phenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
(xe2x88x92)-cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
cis-6-phenyl-5-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol;
cis-1-[6xe2x80x2-pyrrolodinoethoxy-3xe2x80x2-pyridyl]-2-phenyl-6-hydroxy-1,2,3,4-tetrahydronaphthalene;
1-(4xe2x80x2-pyrrolidinoethoxyphenyl)-2-(4xe2x80x3-fluorophenyl)-6-hydroxy-1,2,3,4-tetrahydroisoquinoline;
cis-6-(4-hydroxyphenyl)-5-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-5,6,7,8-tetrahydro-naphthalene-2-ol; or
1-(4xe2x80x2-pyrrolidinolethoxyphenyl)-2-phenyl-6-hydroxy-1,2,3,4-tetrahydroisoquinoline
is in the range of 0.0001 to 100 mg/kg/day, preferably 0.001 to 10 mg/kg/day.
In particular, an effective dosage for 4-hydroxy tamoxifen is in the range of 0.0001 to 100 mg/kg/day, preferably 0.001 to 10 mg/kg/day.
Assay for Stimulation of GH Release from Rat Pituicytes
Compounds that have the ability to stimulate GH secretion from cultured rat pituitary cells are identified using the following protocol. This test is also useful for comparison to standards to determine dosage levels. Cells are isolated from pituitaries of 6-week old male Wistar rats. Following decapitation, the anterior pituitary lobes are removed into cold, sterile Hank""s balanced salt solution without calcium or magnesium (HBSS). Tissues are finely minced, then subjected to two cycles of mechanically assisted enzymatic dispersion using 10 U/mL bacterial protease (EC 3.4.24.4, Sigma P6141, St. Louis, Mo.) in HBSS. The tissue-enzyme mixture is stirred in a spinner flask at 30 rpm in a 5% CO2 atmosphere at about 37xc2x0 C. for about 30 min., with manual trituration after about 15 min. and about 30 min. using a 10-mL pipet. This mixture is centrifuged at 200xc3x97g for about 5 min. Horse serum (35% final concentration) is added to the supernatant to neutralize excess protease. The pellet is resuspended in fresh protease (10 U/mL), stirred for about 30 min. more under the previous conditions, and manually triturated, ultimately through a 23-gauge needle. Again, horse serum (35% final concentration) is added, then the cells from both digests are combined, pelleted (200xc3x97g for about 15 min.), resuspended in culture medium (Dulbecco""s Modified Eagle Medium (D-MEM) supplemented with 4.5 g/L glucose, 10% horse serum, 2.5% fetal bovine serum, 1% non-essential amino acids, 100 U/mL nystatin and 50 mg/mL gentamycin sulfate, Gibco, Grand Island, N.Y.) and counted. Cells are plated at 6.0-6.5xc3x97104 cells per cm2 in 48-well Costar(trademark) (Cambridge, Mass.) dishes and cultured for 3-4 days in culture medium.
Just prior to GH secretion assay, culture wells are rinsed twice with release medium, then equilibrated for about 30 minutes in release medium (D-MEM buffered with 25 mM Hepes, pH 7.4 and containing 0.5% bovine serum albumin at 37xc2x0 C.). Test compounds are dissolved in DMSO, then diluted into pre-warmed release medium. Assays are run in quadruplicate. The assay is initiated by adding 0.5 mL of release medium (with vehicle or test compound) to each culture well. Incubation is carried out at about 37xc2x0 C. for about 15 minutes, then terminated by removal of the release medium, which is centrifuged at 2000xc3x97g for about 15 minutes to remove cellular material. Rat growth hormone concentrations in the supernatants are determined by a standard radioimmunoassay protocol described below.
Measurement of Rat Growth Hormone
Rat growth hormone concentrations were determined by double antibody radioimmunoassay using a rat growth hormone reference preparation (NIDDK-rGH-RP-2) and rat growth hormone antiserum raised in monkey (NIDDK-anti-rGH-S-5) obtained from Dr. A. Parlow (Harbor-UCLA Medical Center, Torrence, Calif.). Additional rat growth hormone (1.5 U/mg, #G2414, Scripps Labs, San Diego, Calif.) is iodinated to a specific activity of approximately 30 xcexcCi/xcexcg by the chloramine T method for use as tracer. Immune complexes are obtained by adding goat antiserum to monkey IgG (ICN/Cappel, Aurora, Ohio) plus polyethylene glycol, MW 10,000-20,000 to a final concentration of 4.3%; recovery is accomplished by centrifugation. This assay has a working range of 0.08-2.5 xcexcg rat growth hormone per tube above basal levels.
Assay for Exogenously-Stimulated Growth Hormone Release in the Rat After Intravenous Administration of Test Compounds
Twenty-one day old female Sprague-Dawley rats (Charles River Laboratory, Wilmington, Mass.) are allowed to acclimate to local vivarium conditions (24xc2x0 C., 12 hr light, 12 hr dark cycle) for approximately 1 week before compound testing. All rats are allowed access to water and a pelleted commercial diet (Agway Country Food, Syracuse N.Y.) ad libitum. The experiments are conducted in accordance with the NIH Guide for the Care and Use of Laboratory Animals.
On the day of the experiment, test compounds are dissolved in vehicle containing 1% ethanol, 1 mM acetic acid and 0.1% bovine serum albumin in saline. Each test is conducted in three rats. Rats are weighed and anesthetized via intraperitonxc3xa8al injection of sodium pentobarbital (Nembutol(copyright), 50 mg/kg body weight). Fourteen minutes after anesthetic administration, a blood sample is taken by nicking the tip of the tail and allowing the blood to drip into a microcentrifuge tube (baseline blood sample, approximately 100 xcexcl). Fifteen minutes after anesthetic administration, test compound is delivered by intravenous injection into the tail vein, with a total injection volume of 1 mL/kg body weight. Additional blood samples are taken from the tail at 5, 10 and 15 minutes after compound administration. Blood samples are kept on ice until serum separation by centrifugation (1430xc3x97g for 10 minutes at 10xc2x0 C.). Serum is stored at xe2x88x9280xc2x0 C. until serum growth hormone determination by radioimmunoassay as described above.
Assessment of Exogenously-Stimulated Growth Hormone Release in the Dog After Oral Administration
On the day of dosing, the test compound is weighed out for the appropriate dose and dissolved in water. Doses are delivered at a volume of 0.5-3 mL/kg by gavage to 2-4 dogs for each dosing regimen. Blood samples (5 mL) are collected from the jugular vein by direct vena puncture pre-dose and at 0.17, 0.33, 0.5, 0.75, 1, 2, 4, 6, 8 and 24 hours post dose using 5 mL vacutainers containing lithium heparin. The prepared plasma is stored at xe2x88x9220xc2x0 C. until analysis.
Measurement of Canine Growth Hormone
Canine growth hormone concentrations are determined by a standard radioimmunoassay protocol using canine growth hormone (antigen for iodination and reference preparation AFP-1983B) and canine growth hormone antiserum raised in monkey (AFP-21452578) obtained from Dr. A. Parlow (Harbor-UCLA Medical Center, Torrence, Calif.). Tracer is produced by chloramine T-iodination of canine growth hormone to a specific activity of 20-40 xcexcCi/xcexcg. Immune complexes are obtained by adding goat antiserum to monkey IgG (ICN/Cappel, Aurora, Ohio) plus polyethylene glycol, MW 10,000-20,000 to a final concentration of 4.3%; recovery is accomplished by centrifugation. This assay has a working range of 0.08-2.5 xcexcg canine GH/tube.
Assessment of Canine Growth Hormone and Insulin-Like Growth Factor-1 Levels in the Dog After Chronic Oral Administration
The dogs receive test compound daily for either 7 or 14 days. Each day of dosing, the test compound is weighed out for the appropriate dose and dissolved in water. Doses are delivered at a volume of 0.5-3 ml/kg by gavage to 5 dogs for each dosing regimen. Blood samples are collected at days 0, 3, 7, 10 and 14. Blood samples (5 ml) are obtained by direct venipuncture of the jugular vein at pre-dose, 0.17, 0.33, 0.5, 0.754, 1, 2, 3, 6, 8, 12 and 24 hours post administration on days 0, 7 and 14 using 5 ml vacutainers containing lithium heparin. In addition, blood is drawn pre-dose and 8 hours on days 3 and 10. The prepared plasma is stored at xe2x88x9220xc2x0 C. until analysis.
Female Rat Study
This study evaluates the effect of chronic treatment with a GHRP mimetic on weight, body composition and non-fasting plasma concentrations of glucose, insulin, lactate and lipids in estrogen-deficient and estrogen-replete female rats. Acute responsiveness of serum GH levels to i.v. administration of the GH releasing agent was assessed on the last day of dosing. Body weight was monitored weekly throughout the treatment period; additionally, body composition and plasma levels of glucose, insulin, lactate, cholesterol and triglycerides were assessed at the end of treatment.
Virgin female Sprague-Dawley rats were obtained from Charles River Laboratories (Wilmington, Mass.) and underwent bilateral ovariectomy (Ovx) or sham-surgery (Sham) at approximately 12 weeks of age. For sham surgeries, ovaries were exteriorized and replaced into the abdominal cavity. Following surgery the rats were housed individually in 20 cmxc3x9732 cmxc3x9720 cm cages under standard vivarium conditions (about 24xc2x0 C. with about 12 hours light/12 hours dark cycle). All rats were allowed free access to water and a pelleted commercial diet (Agway ProLab 3000, Agway Country Food, Inc., Syracuse, N.Y.). The experiment was conducted in accordance with NIH Guidelines for the Care and Use of Laboratory Animals.
Approximately seven months post-surgery, Sham and Ovx rats were weighed and randomly assigned to groups. Rats were dosed daily by oral gavage with 1 mL of either vehicle (1% ethanol in distilled-deionized water), 0.5 mg/kg or 5 mg/kg of a growth hormone releasing agent for 90 days. Rats were weighed at weekly intervals throughout the study. Twenty-four hours after the last oral dose, the acute response of serum growth hormone (GH) to test agent was assessed by the following procedure. Rats were anesthetized with sodium pentobarbital 50 mg/kg. Anesthetized rats were weighed and a baseline blood sample (xcx9c100 xcexcl) was collected from the tail vein. Test agent (growth hormone releasing agent or vehicle) was then administered intravenously via the tail vein in 1 mL. Approximately ten minutes after injection, a second 100 xcexcl blood sample was collected from the tail. Blood was allowed to clot at about 4xc2x0 C., then centrifuged at 2000xc3x97g for about 10 minutes. Serum was stored at about xe2x88x9270xc2x0 C. Serum growth hormone concentrations were determined by radioimmunoassay as previously described. Following this procedure, each anesthetized rat underwent whole body scanning by dual-energy X-ray absorptiometry (DEXA, Hologic QDR 10001/W, Waltham Mass.). A final blood sample was collected by cardiac puncture into heparinized tubes. Plasma was separated by centrifugation and stored frozen as described above.
Plasma insulin is determined by radioimmunoassay using a kit from Binax Corp. (Portland, Me.). The interassay coefficient of variation is xe2x89xa610%. Plasma triglycerides, total cholesterol, glucose and lactate levels are measured using Abbott VP(trademark) and VP Super System(copyright) Autoanalyzer (Abbott Laboratories, Irving, Tex.), using the A-Gent(trademark) Triglycerides, Cholesterol and Glucose Test reagent systems, and a lactate kit from Sigma, respectively. The plasma insulin, triglycerides, total cholesterol and lactate lowering activity of a growth hormone releasing peptide (GHRP) or GHRP mimetic such as a compound of Formula I, are determined by statistical analysis (unpaired t-test) with the vehicle-treated control group.
The compounds of this invention can be administered by oral, parenteral (e.g., intramuscular, intraperitoneal, intravenous or subcutaneous injection, or implant), nasal, vaginal, rectal, sublingual, or topical routes of administration and can be formulated with pharmaceutically acceptable carriers to provide dosage forms appropriate for each route of administration.
Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules and for companion animals the solid dosage forms include an admixture with food and chewable forms. In such solid dosage forms, the active compound is admixed with at least one inert pharmaceutically acceptable carrier such as sucrose, lactose, or starch. Such dosage forms can also comprise, as is normal practice, additional substances other than such inert diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents. Tablets and pills can additionally be prepared with enteric coatings. In the case of chewable forms, the dosage form may comprise flavoring agents and perfuming agents.
Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, the elixirs containing inert diluents commonly used in the art, such as water. Besides such inert diluents, compositions can also include adjuvants, such as wetting agents, emulsifying and suspending agents, and sweetening, flavoring and perfuming agents.
Preparations according to this invention for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions, or emulsions. Examples of non-aqueous solvents or vehicles are propylene glycol, polyethylene glycol, vegetable oils, such as olive oil and corn oil, gelatin, and injectable organic esters such as ethyl oleate. Such dosage forms may also contain adjuvants such as preserving, wetting, emulsifying, and dispersing agents. They may be sterilized by, for example, filtration through a bacteria-retaining filter, by incorporating sterilizing agents into the compositions, by irradiating the compositions, or by heating the compositions. They can also be manufactured in the form of sterile solid compositions which can be dissolved in sterile water, or some other sterile injectable medium immediately before use.
Compositions for rectal or vaginal administration are preferably suppositories which may contain, in addition to the active substance, excipients such as coca butter or a suppository wax.
Compositions for nasal or sublingual administration are also prepared with standard excipients well known in the art.
The dosage of active ingredient in the compositions of this invention may be varied; however, it is necessary that the amount of the active ingredient be such that a suitable dosage form is obtained. The selected dosage depends upon the desired therapeutic effect, on the route of administration, and on the duration of the treatment. Generally, dosage levels of between 0.0001 to 100 mg/kg of body weight daily are administered to humans and other animals, e.g., mammals, to obtain effective release of growth hormone.
A preferred dosage range in humans is 0.01 to 5.0 mg/kg of body weight daily which can be administered as a single dose or divided into multiple doses.
A preferred dosage range in animals other than humans is 0.01 to 10.0 mg/kg of body weight daily which can be administered as a single dose or divided into multiple doses. A more preferred dosage range in animals other than humans is 0.1 to 5 mg/kg of body weight daily which can be administered as a single dose or divided into multiple doses.
Throughout this disclosure the following abbreviations are used with the following meanings:
BOC t-Butyloxycarbonyl
Bz Benzyl
BOP Benzotriazol-1-yloxy tris(dimethylamino)phosphonium hexafluorophosphate
CBZ Benzyloxycarbonyl
CDI N,Nxe2x80x2-Carbonyldiimidazole
DCC Dicyclohexylcarbodiimide
DEC 1,2-Diethylaminoethyl chloride hydrochloride
DMAP 4-Dimethylaminopyridine
DMF Dimethylformamide
DPPA Diphenylphosphoryl azide
EDC 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride
EtOAc Ethyl acetate
Hex Hexane
HOAT 1-Hydroxy-7-azabenzotiazole
HOBT Hydroxybenzotriazole hydrate
HPLC High pressure liquid chromatography
Hz Hertz
KHMDS Potassium Bis(trimethylsilyl)amide
LHMDS Lithium Bis(trimethylsilyl)amide
MHz Megahertz
MS Mass Spectrum
NaHMDS Sodium Bis(trimethylsilyl)amide
NMR Nuclear Magnetic Resonance
PPAA 1-Propanephosphonic acid cyclic anhydride
PTH Parathyroid hormone
TFA Trifluoroacetic acid
THF Tetrahydrofuran
TLC Thin layer chromatography
TRH Thyrotropin releasing hormone
The preparation of the compounds of Formula I of the present invention can be carried out in sequential or convergent synthetic routes. Syntheses detailing the preparation of the compounds of Formula I in a sequential manner are presented in the following reaction schemes.
Many protected amino acid derivatives are commercially available, where the protecting groups, Prt, Prtxe2x80x2 or Prtxe2x80x3, are, for example, BOC, CBZ, FMOC, benzyl or ethoxycarbonyl groups. Other protected amino acid derivatives can be prepared by literature methods well-known to one skilled in the art. Some substituted piperazines and piperidines are commercially available, and many other piperazines and 4-substituted piperidines are known in the literature. Various heterocyclic substituted piperidines and piperazines can be prepared following literature methods using derivatized heterocyclic intermediates. Alternatively, the heterocyclic rings of such compounds can be derivatized by standard means, such as coupling with CDI, hydrogenation of aromatic heterocycles, etc. as is well-known to those skilled in the art.
Many of the schemes illustrated below describe compounds which contain protecting groups Prt, Prtxe2x80x2 or Prtxe2x80x3, which can be any suitable protecting group known to those skilled in the art. Benzyloxycarbonyl groups can be removed by a number of methods including, catalytic hydrogenation with hydrogen in the presence of a palladium or platinum catalyst in a protic solvent such as methanol. Preferred catalysts are palladium hydroxide on carbon or palladium on carbon. Hydrogen pressures from 1-1000 psi can be employed; pressures from 10 to 70 psi are preferred. Alternatively, the benzyloxycarbonyl group can be removed by transfer hydrogenation.
Removal of BOC protecting groups can be carried out using a strong acid such as trifluoroacetic acid or hydrochloric acid with or without the presence of a cosolvent such as dichloromethane or methanol at a temperature of about xe2x88x9230xc2x0 to 70xc2x0 C., preferably about xe2x88x925xc2x0 to about 35xc2x0 C.
Benzyl groups on amines can be removed by a number of methods including catalytic hydrogenation with hydrogen in the presence of a palladium catalyst in a protic solvent such as methanol. Hydrogen pressures from 1-1000 psi can be employed; pressures from 10 to 70 psi are preferred. The addition and removal of these and other protecting groups are discussed in detail by T. Greene in Protective Groups in Organic Synthesis, John Wiley and Sons, New York, 1981.
The variables shown in the following schemes are as described for compounds of Formula I, above, unless otherwise indicated. 
As illustrated in Scheme 1, coupling of a heterocyclic amine (HET at the NH) of formula 1-2, as defined for Formula I, with a protected amino acid of formula 1-1, where Prt is a suitable protecting group, is conveniently carried out in an inert solvent such as dichloromethane or DMF by a coupling reagent such as EDC, DCC or DEC in the presence of HOBT or HOAT. In the case where amine 1-2 is present as the hydrochloride salt, it is preferable to add one equivalent of a suitable base such as triethylamine to the reaction mixture. Alternatively, the coupling can be effected with a coupling reagent such as BOP in an inert solvent such as methanol or with PPM in a solvent like ethyl acetate. Such coupling reactions are generally conducted at temperatures of about xe2x88x9230xc2x0 to about 80xc2x0 C., preferably 0xc2x0 to about 25xc2x0 C. For a discussion of other conditions used for coupling peptides see Houben-Weyl, Vol. XV, part II, E. Wunsch, Ed., George Theime Verlag, 1974, Stuttgart. Separation of unwanted side products and purification of intermediates is achieved by chromatography on silica gel, employing flash chromatography (W. C. Still, M. Kahn and A. Mitra, J. Org. Chem. 43 2923 1978), by crystallization, or by trituration. Transformation of 1-3 into an intermediate of formula 1-4 can be carried out by removal of the protecting group Prt as described above. 
As illustrated in Scheme 2, coupling of a heterocyclic amine of formula 1-2, as defined in claim 1, with an amino acid of formula 2-1, where R7 and R8 are not hydrogen, is conveniently carried out in a manner similar to that described in Scheme 1. 
As illustrated in Scheme 3, an intermediate ether of formula 3-2 can be prepared by treating an amino acid of formula 3-1, where Prt is a suitable protecting group, with a base such as potassium carbonate or sodium hydride followed by an alkyl halide, benzyl halide, tosylate or mesylate such as benzylbromide in a suitable solvent such as DMF or THF. Deprotection of the amine transforms 3-2 into 3-3. Alternatively, many amino acids of formula 3-3 are commercially available. R is a group defined for R3 in Formula I, above. 
As illustrated in Scheme 4, intermediates of formula 4-2 can be prepared by treating an acid of formula 4-1 with hydroxysuccinimide in the presence of a coupling agent such as EDC in an inert solvent such as methylene chloride. Treating 4-2 with an amino acid of formula 4-3 in a solvent such as DMF in the presence of a base such as diisopropylethylamine produces compounds of formula 1-1. 
As illustrated in Scheme 5, dipeptides of formula 2-1, where R7 and R8 are not hydrogen, is conveniently synthesized by the procedures described in Scheme 4. 
Intermediate esters of formula 6-2, where Prt and Prtxe2x80x2 are protecting groups, preferrably Prtxe2x80x2 is a carbamate protecting group such as CBZ, can be prepared by treating an acid of formula 6-1 with a base such as potassium carbonate followed by an alkyl halide such as iodomethane in a suitable solvent such as DMF. Alternatively, an ester of formula 6-2 can be prepared by reacting an acid of formula 6-1 with diazomethane. For the preparation of compound 6-2 see Bigge, C. F. et al., Tet. Lett., 1989, 30, 5193-5196. Intermediate 6-4 is generated by alkylating ester 6-2 with a reagent such as an alkyl halide, tosylate or mesylate with a base such as NaHMDS in a suitable solvent system such as DMF/THF at a temperature of about xe2x88x9278xc2x0 C.
Intermediate carbamates of formula 6-5 can be prepared by reacting an intermediate of formula 6-4 with a hydride such as sodium borohydride or superhydride. Transformation of intermediate 6-5 to 6-6 can be achieved by removal of the protecting group Prt as described above. 
Transformation of intermediate 6-4 to 7-1 can be achieved by removal of the protecting group Prtxe2x80x2 as described above. Intermediate ureas of formula 7-5 can be prepared by reacting an intermediate of formula 7-1 with either an acyl imidizolide of formula 7-2, an isocyanate of formula 7-3, or phosgene (or other phosgene equivalent) followed by an amine of formula 7-4 in the presence of a suitable base such as triethylamine. When R1 is xe2x80x94CH2-pyridyl it is preferred to use an isocyanate or acyl imidizolide. Transformation of 7-5 to 7-6 can be achieved by removal of the protecting group Prt as described above. 
An intermediate benzylamine of formula 8-1 can be prepared by treating an amine of formula 7-1 with a base such as diisopropylethylamine followed by a benzyl halide such as benzyl bromide in a suitable solvent such as acetonitrile. Alternatively, 8-1 can be prepared by treating 7-1 with benzaldehyde and a suitable reducing agent such as NaCNBH3 or Na(OAc)3BH in a suitable solvent such as methanol or dichloromethane. An alcohol of the formula 8-2 can be prepared by reducing an intermediate of the formula 8-1 with a reducing agent such as superhydride in a suitable solvent such as THF. An alcohol of the formula 8-2 can be oxidized to an aldehyde of the formula 8-3 with an oxidizing agent such as oxalyl chloride/DMSO in a suitable solvent such as dichloromethane at a temperature of about xe2x88x9278xc2x0 C., with the later addition of a base such as triethylamine to neutralize the reaction mixture (SweRN-type oxidation, see Mancuso, A. J., SweRN, D., Syhthesis, 1981, pp. 165-185). Compounds of formula 8-5 can be prepared by treating an aldehyde of formula 8-3 with an amine of formula 8-4 in the presence of a suitable reducing agent which include alkali metal borohydrides and cyanoborohydrides. The preferred reducing agent is sodium cyanoborohydride. Sodium borohydride and sodium triacetoxyborohydride may also be used. For a general review of reductive aminations see R. F. Borch, Aldrichimica Acta, 8, 3-10 (1975). Removal of the benzyl group to give 8-6 can be accomplished by a number of reductive methods including hydrogenation in the presence of platinum or palladium catalyst in a protic solvent such as methanol. Cyclization of a diamine of formula 8-6 with CDI or other phosgene equivalents generates a compound of formula 8-7. Removal of the protecting group, as described above, transforms 8-7 into 8-8. 
As illustrated in Scheme 9, an intermediate hydantoin of formula 9-4 can be prepared in three steps. An ester of formula 9-1, prepared by cleavage of Prtxe2x80x2 from 6-2, can be acylated with an acyl imidizolide of formula 7-2, an isocyanate of formula 7-3, or phosgene (or other phosgene equivalent) followed by an amine of formula 7-4 in the presence of a suitable base such as triethylamine. Transformation of 9-3 to 9-4 can be accomplished by removal of the protecting group Prt as described above. 
Intermediates of formula 10-1 can be prepared by treating a compound of formula 7-1 with an acyl chloride or other activated carboxylic acid derivative and a suitable base, such as TEA or N,N-diisopropylethylamine. Cyclization of a compound of formula 10-1 occurs upon treating 10-1 with a strong base such as LHMDS at a suitable temperature, about xe2x88x9278xc2x0 C. to 40xc2x0 C., to produce an intermediate of formula 10-2. When R9 and/or R10 is H, 10-2 may be alkylated with a reagent such as methyl iodide in the presence of a base like NaH to give 10-2 where R9 and R10 are not H. Removal of the protecting group, as described above, transforms 10-2 to 10-3. 
Intermediate xcex1,xcex2-unsaturated esters of formula 11-3 (R is an alkyl group) can be prepared by olefinating 11-1 with a reagent such as the anion generated upon treating trimethylphosphonoacetate with a strong base such as potassium tert-butoxide in a suitable solvent such as THF. Catalytic hydrogenation, such as with Pd on carbon in the presence of hydrogen, preferably at 1-4 atmospheres, in a suitable solvent, such as ethyl acetate or methanol, reduces the double bond of 11-3 to produce 11-4. Selective hydrolysis of the less hindered ester group in 11-4 can be performed with a base such as an alkali metal hydroxide in an appropriate solvent, such as a mixture of water, methanol, and/or dioxane. A carboxylic acid of formula 11-5, thus produced can be transformed to 11-6 by converting 11-5 to an acyl azide, such as with DPPA and TEA in benzene, followed by rearrangement to an isocyanate by heating to reflux in a solvent such as benzene, which is then reacted with benzyl alcohol to form 11-6. A lactam of formula 11-7 can be prepared by removal of the CBZ protecting group from the amine in 11-6, followed by cyclization of the amine with the adjacent ester group. Deprotection of this material provides 11-9, R2 =H. Alternatively, amide 11-7 can be alkylated by deprotonation with a strong base such as sodium hydride, LHMDS, or KHMDS in a suitable solvent such as DMF or THF followed by treatment with an alkylating agent such as an alkyl halide, mesylate or tosylate. The product, 11-8, may then be deprotected, as described above, to provide 11-9. One skilled in the art will recognize that substitution next to the lactam nitrogen could have been introduced by alkylating ester 11-4 or by olefinating 11-1 to give a tetra-substituted olefin analogous to 11-3. 
Intermediate enol ethers of formula 12-1 can be prepared by treating 11-1 (R is an alkyl group) with a reagent, such as methoxymethyl triphenylphosphonium chloride and a strong base, such as potassium tert-butoxide, in a suitable solvent such as THF. Hydrolysis of an enol ether of formula 12-1 under acidic conditions produces aldehyde 12-2. Reduction of the aldehyde group to an alcohol, for example with sodium borohydride in methanol, followed by cyclization converts 12-2 to a lactone of formula 12-3. Deprotection of the nitrogen, as described above, affords 12-4. One skilled in the art will recognize that an R1A substituent could have been introduced by alkylating aldehyde 12-2. In addition, substitution next to the lactone oxygen (R9/R10) could be introduced by olefinating 11-1 to give a tetra-substituted olefin and by treating the latter ketone or aldehyde (12-2) with an alkyl metal such as a Grignard reagent. 
Reduction of the ketone in 11-1 (R is an alkyl group) to an alcohol with a suitable reducing reagent, such as with sodium borohydride in methanol, converts 11-1 to 13-1. Hydrolysis of the ester group in 13-1 according to the method discussed in Scheme 11 produces acid 13-2. Transformation of 13-2 to 13-3 can be achieved by converting 13-2 to acyl azides, for instance with DPPA and TEA in a solvent such as benzene, followed by rearrangement to isocyanates, which then react intramolecularly with the adjacent alcohol to form carbamate 13-3. Deprotection of 13-3 as described above would provides 13-5 where R2 is H. Alternatively, carbamate 13-3 can be alkylated by deprotonation with a strong base such as sodium hydride, LHMDS, or KHMDS in a suitable solvent such as DMF or THF followed by treatment with an alkylating agent such as an alkyl halide (R2-halide), mesylate or tosylate. Removal of the protecting group, as described above, transforms 13-4 to 13-5. One skilled in the art will recognize that an R1A substituent could have been introduced by treating ketone 11-1 with an alkyl metal reagent, such as methyl magnesium bromide, at a suitable temperature for a Grignard reaction. 
Removal of the carbamate protecting group, Prt, from 11-1 (R is an alkyl group) produces 14-1. Reprotection, such as with a benzyl group gives 14-2. Treating 14-2 with hydroxylamine yields an oxime of formula 14-3. The oxime and ester groups in 14-3 can be reduced to an amine and alcohol, respectively, to form 14-4 with a suitable reducing reagent, such as with LAH in THF. Transformation of 14-4 to a carbamate of formula 14-5 can be achieved by reaction of 14-4 with CDI or another phosgene equivalent in the presence of a base like TEA and solvent such as DME. Deprotection of 14-5 produces 14-7 where R2 is H. Alternatively, alkylation of the carbamate as described above (Scheme 13) affords 14-6, which can be deprotected, as described above, to give 14-7. 
Treating 15-1 with a strong base such as sodium hydride in a suitable solvent such as DMF, followed by treatment with an alkylating agent, such as an alkyl halide, mesylate or tosylate, produces an N-substituted imide of formula 15-2. Reduction of the pyridine ring by catalytic hydrogenation, such as with Pd on carbon in an ethanolic HCI solution converts 15-2 to 15-3. Protection of the nitrogen, such as with a benzyl group, gives 15-4. A compound of the formula 15-5 can be generated upon deprotonation of 15-4 with a suitable strong base such as LHMDS in a solvent such as THF at a temperature of about xe2x88x9278xc2x0 C., followed by alkylation with an electrophile such as an alkyl halide such as benzyl bromide. Cleavage of the protecting group, as described above, then gives 15-6. 
Deprotection of 16-1 as described above produces 16-2. 
Condensation of 17-1 (R is an alkyl group) with an amidine in a solvent such as ethanol at an elevated temperature, preferably refluxing solvent, produces a heterocyclic intermediate of formula 17-2. Deprotection of 17-2, as described above, gives an intermediate of formula 17-3. 
An intermediate amine of formula 18-2 can be prepared from a ketone of formula 11-1 (R is an alkyl group) by reductive amination as described above (see Scheme 8). Protection of the secondary amine in 18-2 produces 18-3. Intermediate carboxylic acids of formula 18-4 can be prepared by hydrolysis of the ester group of formula 18-3 (see Scheme 11). Transformation of 18-4 to 18-5 can be achieved through an intermediate acyl azide as described above (see Scheme 11). Cyclization of an intermediate of formula 18-5 at a suitable temperature after removing Prtxe2x80x2 yields an intermediate urea of formula 18-6. Deprotection of 18-6 provides 18-8 where R2xe2x80x2 is H. Alternatively, urea 18-6 can be alkylated by deprotonation with a strong base such as sodium hydride, LHMDS, or KHMDS in a suitable solvent such as DMF or THF followed by treatment with an alkylating agent such as an alkyl halide, mesylate or tosylate. Removal of the protecting group transforms 18-7 to 18-8 where R2 and R2xe2x80x2 are each alkyl. 
As illustrated in Scheme 19, reduction of a ketoester of formula 19-1, such as with sodium borohydride in methanol, preferably at 0xc2x0 C., produces an alcohol of formula 19-2. An intermediate of formula 19-3 can be prepared by protection of the hydroxyl group in an intermediate of formula 19-2 with a suitable protecting group, such as forming a tetrahydropyranyl acetal or silyl ether. Transformation of the ester of formula 19-3 to amide 19-5 can be achieved as described above (see Scheme 11). Deprotection of the hydroxy group of 19-5 yields the free alcohol intermediate, which can be oxidized to an intermediate ketone of formula 19-6 with a suitable oxidizing agent, such as pyridinium chlorochromate or a Swern-type reagent (see cheme 8). Transformation of 19-6 to a cyclized carbamate of formula 19-7 can be achieved by treating 19-6 with an alkyl metal, such as a Grignard reagent, in a suitable solvent such as THF, followed by cyclization. Removal of the protecting group then yields 19-9 wherein R2 is H. Alternatively, the carbamate of 19-7 may be alkylated as described above (see Scheme 13) to afford 19-8, which can then be deprotected to provide 19-9. Those skilled in the art will recognize that an R1A substituent could have been introduced by alkylating ketoester 19-1. 
An alternate synthesis of lactam 11-7 is illustrated in Scheme 20. An alcohol of formula 13-1 can be,converted to an intermediate nitrile of formula 20-1 by first activating the hydroxyl of 13-1 (R is an alkyl group), such as with methanesulfonyl chloride or methanesulfonic acid in a suitable solvent, such as methylene chloride in the presence of an amine base. Subsequent reaction of 20-1 (LOxe2x80x94 is an activated hydroxyl) with a cyanide salt, such as potassium cyanide, then yields an intermediate nitrile of formula 20-2, which can be transformed to 11-7 by catalytic hydrogenation of the nitrile to amine, which then reacts with the ester group to form lactam (11-7). Those skilled in the art will recognize that an R1A substituent could be introduced by alkylating nitrile 20-2. 
Nitriles of formula 21-1 can be prepared from esters, acid halides and acids of formula 11-1 by a variety of known methods (for examples, see R. Larock pages 976, 980 and 988 in Comprehensive Organic Transformations: A Guide to Functional Group Preparations, VCH Publishers, 1989).
Homologation of ketones of formula 21-1 to provide 21-3 as described above (Scheme 12) yields an aldehyde of formula 21-3. Oxidation of the aldehyde group in 21-3, such as with sodium hypochlorite, provides an acid which can be esterified to give 21-4 by a number of methods described above (Scheme 6). Reduction of the nitrile group in a compound of formula 21-4, such as by catalytic hydrogenation over Pd on carbon, gives an amine which will cyclize to give a lactam of formula 21-5. Deprotection of 21-5 yields 21-7, R2 is H. Alternatively, alkylation of the amide of formula 21-5 as described above (Scheme 11) yields an N-substituted amide of formula 21-6, which can be deprotected to provide 21-7. Those skilled in the art will recognize that an R1A substituent could have been introduced by alkylating ester 21-4. 
Intermediate alcohols of formula 22-1 can be prepared by reducing the ketone and ester groups of 11-1 (R is an alkyl group), such as with a metal borohydride or lithium aluminum hydride in a suitable solvent such as THF. Selective protection of the primary hydroxyl group of the intermediate of formula 22-1 with a suitable protecting group, such as a trialkylsilyl ether or pivaloyl ester gives a secondary alcohol of formula 22-2. An intermediate nitrile of formula 22-4 can be prepared from the alcohol of formula 22-2 by methods described above (see Scheme 20). An intermediate nitrile of formula 22-4 can be transformed to an ester of formula 22-5 by alcoholysis of nitrile 22-4, for instance with aqueous HCl or sodium hydroxide in ethanol. Removal of the alcohol protecting group and reaction of the hydroxyl group with the adjacent ester group in 22-5 forms a lactone of formula 22-6. Deprotection as described above yields 22-7. Those skilled in the art will recognize that an R1A substituent could have been introduced by treating ketone 11-1 with the appropriate alkyl metal reagent. Substitution (R9, R10) adjacent to the lactone oxygen could then be introduced by treating the ester with the appropriate alkyl metal reagent (the ketone would have to be reduced if R1A is not O). 
Intermediate xcex1,xcex2-unsaturated nitrites of formula 23-1 can be prepared by olefinating 11-1 (R is an alkyl group) with a reagent such as cyanomethyltriphenylphosphonium chloride and a strong base, such as KHMDS, in a suitable solvent, such as THF. Reduction of the double bond in 23-1, such as with sodium borohydride in pyridine, produces nitrile 23-2. The ester group of formula 23-2 can then be transformed to a carbamate of formula 23-4 by methods described above (see Scheme 11). Alcoholysis of the nitrile of 23-4 in an alcoholic solvent under acidic condition produces an ester of formula 23-5. A lactam of formula 23-6 can be prepared by removal of the CBZ protecting group, followed by cyclization of the amine with the adjacent ester group. Deprotection at this stage provides 23-8, R2 is H. Alternatively, alkylation of the amide (according to Scheme 11) provides an N-subsitituted lactam, which can be converted to 23-8 by deprotection as described above. One skilled in the art will recognize that an R1A substituent could have been introduced by conjugate addition to the unsaturated nitrile (23-1), such as with an alkyl cuprate. In addition, R9, R10 substituents can be introduced next to the lactam carbonyl by alkylating nitrile 23-2. 
As illustrated in Scheme 24, an alcohol of formula 24-1 can be prepared from 19-3 (R is an alkyl group) by reduction of the ester with a reducing reagent such as lithium borohydride in a solvent such as THF. A nitrile of formula 24-2 can be prepared from the alcohols of formula 24-1 by methods described above (see Scheme 20). Deprotection of the alcohol of 24-2 followed by oxidation of the hydroxyl as previously described (see Scheme 19) produces a ketone 24-3. Treating 24-3 with an alkyl metal such as a Grignard reagent in a suitable solvent such as THF gives an intermediate of formula 24-4. The cyano group of 24-4 can then be converted to an ester by alcoholysis as described above (Scheme 22). Reaction of the tertiary alcohol with the neighboring ester forms a lactone which can then be deprotected to give 24-5. One skilled in the art will recognize that an R1A substituent could be introduced by alkylating ester 19-3. In addition, R9, R10 substituents could be introduced adjacent to the lactone carbonyl by alkylation before final deprotection. 
Intermediate of formula 25-1 (LOxe2x80x94 is an activated hydroxyl) can be prepared y selective activation of the primary hydroxyl, for instance by tosylation of the less hindered hydroxyl group of 20-1 with tosyl chloride in a suitable solvent. Treating 25-1 with a reagent such as potassium cyanide in a suitable solvent produces a nitrile of formula 25-2. Oxidation of the alcohol (see Scheme 19) of formula 25-2 gives a ketone of formula 25-3. Transformation of 25-3 to 25-4 can be achieved by reductive amination as was described above (see Scheme 8). The cyano amine of formula 25-4 can be converted to a lactam of formula 25-5 by treating 25-4 with a strong acid or base in a protic solvent such as ethanol. Removal of the protecting group on the secondary nitrogen can then provide lactam 25-6. One skilled in the art will recognize that R9, R10 substituents could be introduced by alkylation of lactam 25-5. 
A lactone of formula 26-1 can be prepared by treating a cyano alcohol of formula 25-2 with a strong acid such as HCl, or a strong base such as NaOH, in a protic solvent such as EtOH. Deprotection, as described above, of the secondary amine of formula 26-1 gives 26-2. One skilled in the art will recognize that R9, R10 substituents can be introduced by alkylation of lactone 26-1. 
Intermediates of formula 27-1 can be prepared by reducing a lactam of formula 11-7 to a pyrrolidine with a suitable reducing reagent such as borane or lithium aluminum hydride in a suitable solvent such as THF. Treating 27-1 with an acyl chloride of formula RCOCl (where R is an alkyl group) in a suitable solvent produces an intermediate amide of formula 27-2. Removal of the protecting group of the amide of formula 27-2 by the method described previously gives an amide of formula 27-3.
A sulfonamide of formula 27-5 can be prepared by treating 27-1 with a sulfonate such as tosyl chloride in the presence of a base such as pyridine to yield 27-4, followed by removal of the protecting group as previously described. 
Intermediate diols of formula 28-1 (R is an alkyl group) can be prepared by treating 12-2 with a suitable reducing agent, such as lithium borohydride, in an appropriate solvent, such as THF. Methods for converting diol 28-1 to furan 28-2 include dehydration under acidic conditions, dehydration with a reagent such as Ph3P(OEt)2, or reaction with a reagent such as toluenesulfonylchloride in the presence of a base followed by displacement of the activated alcohol with the remaining hydroxyl group. Removal of the protecting group from 28-2 subsequently forms a compound of formula 28-3. One skilled in the art will recognize that an R1A substituent can be added by alkylating aldehyde 12-2. In addition, R9, R10 substituents can be introduced by treating 12-2 with an alkyl metal reagent. 
Intermediate aldehydes of formula 29-1 can be prepared by protecting the secondary alcohol of 13-1 such as with a silyl ether, followed by reduction of the ester with a reducing reagent such as diisobutylaluminum hydride at xe2x88x9278xc2x0 C. in a suitable solvent. Altematively, 13-1 can be reduced to the primary alcohol with a reagent such as lithium borohydride, and then oxidized to the aldehyde with a variety of reagents described above (see Scheme 8). Homologation of aldehydes of formula 29-1 to saturated esters of formula 29-3 can be performed as previously described (see similar homologation of ketones in Scheme 11). Deprotection of the secondary alcohol of 29-3, followed by cyclization produces lactones of formula 29-4. Deprotection of 29-4 will then give 29-5. An R9 substituent xcex2 to the lactone carbonyl may be introduced by conjugate addition to unsaturated ester 29-2, such as with an alkyl cuprate. In addition, R9, R10 substituents could be introduced next to the lactone carbonyl by alkylating lactone 29-4. 
Intermediate ketones of formula 30-1 can be prepared by deprotecting the secondary hydroxyl of 29-3 (R is an alkyl group), followed by oxidation of the alcohol to a ketone (see Scheme 19). Reductive amination of 30-1 with a primary amine as previously described (see Scheme 8) produces intermediate 30-3. Cyclization of 30-3 at a suitable temperature yields a lactam of formula 30-4, which can be deprotected to give 30-5. One skilled in the art will recognize that R9, R10 substituents can be introduced by alkylation of lactam 30-4. 
Homologation of 19-3 (R is an alkyl group) to an ester of formula 31-3 can be performed analogously to routes described above (see Scheme 29). Removal of Prtxe2x80x2 of 31-3 gives a secondary alcohol which can be oxidized as was previously described (see Scheme 19) to produce a ketone of formula 31-4. Treating 31-4 with an alkyl metal reagent, such as a Grignard reagent, in a suitable solvent produces intermediate 31-5, which can be cyclized to form lactone 31-6. Removal of the protecting group then produces 31-7. One skilled in the art will recognize that an R1A substituent may be introduced by alkylation of ester 19-3. A substituent xcex2 to the lactone carbonyl may be introduced by conjugate addition to unsaturated ester 31-2, such as with an alkyl cuprate. Also, R9, R10 substituents can be introduced next to the lactone by alkylation of 31-6. 
Intermediate diols of formula 32-1 can be prepared by reducing the lactone group of 26-2 with a reagent such as lithium aluminum hydride in a suitable solvent such as THF at a suitable temperature. Selective protection at the less hindered hydroxy group of 32-1, such as with t-butyldimethylsilyl chloride using triethylamine in the presence of DMAP in a solvent such as dichloromethane, produces alcohol 32-2. Conversion of alcohol 32-2 to a nitrile of formula 32-4 may be accomplished as described above (LOxe2x80x94 is an activated hydroxyl group) (see Scheme 20). Alcoholysis of the cyano group of formula 32-4 (see Scheme 22), deprotection of the alcohol, and subsequent lactonization forms lactones of formula 32-5.
Deprotection of an amine of formula 32-5 gives a lactone of formula 32-6. One skilled in the art will recognize that R9, R10 substituents can be introduced xcex2- to the ring oxygen in lactone 32-6 by alkylating lactone 26-2. Substitution a to the lactone ring oxygen may be introduced by treating 26-2 with an alkyl metal reagent. 
Intermediate nitriles of formula 33-2 can be prepared by homologating 12-2 (R is an alkyl group), analogous to the ketone homologation described in Scheme 23. Conversion of ester 33-2 to carbamates of formula 33-4 can be accomplished as described above (see Scheme 11). Alcoholysis of the cyano group of 33-4 as described above (see Scheme 22) and removal of the CBZ protecting group, followed by cyclization of the amine with the adjacent ester group produces a lactam of formula 33-5. Deprotection of 33-5 gives the lactam of formula 33-6.
Alternatively, alkylation of 33-5 in the usual fashion (see Scheme 11) gives 33-7, which can be deprotected to give 33-8. One skilled in the art will recognize that an R1A substituent may be introduced by alkylating aldehyde 12-2. An R9 substitutuent may be introduced by conjugate addition to the unsaturated nitrile (33-1). R9, R10 substitution can be introduced next to the lactam by alkylation of 33-7. 
The homologation of 25-3 to give a lactam of formula 34-5 can be analogously performed according to the procedures described in Scheme 21. One skilled in the art will recognize that an R1A substituent may be introduced by alkylating 34-4 (R is an alkyl group). R9, R10 substitution may be introduced by alkylating nitrile 34-1. 
As illustrated in Scheme 35, catalytic hydrogenation of a nitrile of formula 23-2 (R is an alkyl group) gives an amine, followed by cyclization of the amine with the adjacent ester group to give lactams of formula 35-1. Deprotection of 35-1 gives 35-3, R2 is H. Altematively, alkylation of lactam 35-1 as described above (see Scheme 11) provides N-substituted amides of formula 35-2. Deprotection of 35-2 affords 35-3. One skilled in the art will recognize that an R1A substituent may be introduced by conjugate addition to the unsaturated nitrile. 
As illustrated in Scheme 36, selective reduction of the carboxylic acid group of 11-5 to an alcohol, such as by treating 11-5 (R is an alkyl group) with borane in a suitable solvent, followed by cyclization of the alcohol and ester produces a lactone of the formula 36-1. Deprotection of 36-1 then gives 36-2. 
Intermediate alcohols of formula 37-1 can be prepared by reducing the ketone of 21-1, such as with sodium borohydride in a solvent such as methanol at a temperature of about 0xc2x0 C. Reduction of the cyano group to an amine, such as by catalytic hydrogenation, affords aminoalcohol 37-2. Treating 37-2 with a reagent like CDI or other phosgene equivilent in the presence of a base like TEA (see Scheme 14) produces a cyclized carbamate of formula 37-3. Deprotection of 37-3 then gives 37-5, R2 is H. Alternatively, 37-3 may be alkylated as described above (see Scheme 13) to give an N-substituted carbamate of formula 37-4, which is deprotected to give 37-5. One skilled in the art will recognize that an R1A substituent may be introduced by addition to ketone 21-1. 
Intermediate aminoalcohols of formula 38-1 can be prepared by reducing an ester of formula 18-2 (R is an alkyl group), such as with lithium borohydride. Treating 38-1 with a phosgene equivalent as described in Scheme 14 produces a cyclized carbamate of formula 38-2. Deprotection subsequently provides 38-3. 
Intermediate imines of formula 39-1 can be prepared by condensing the ketone of 21-1 with a primary amine under dehydrating conditions, such as azeotropic distillation using a solvent like benzene. Catalytic hydrogenation to reduce the nitrile and imine converts 39-1 to 39-2. Treating 39-2 with a reagent like CDI, phosgene, or triphosgene in the presence of a base like TEA produces the cyclized and N-substituted ureas of formula 39-3. Deprotection of this material provides 39-5 where the R2 attached to the (2)-nitrogen is H. Alkylation of 39-3, such as with sodium hydride and an alkyl halide produces the N,Nxe2x80x2-substituted ureas of formula 39-4, which can be deprotected to provide 39-5 where the R2 attached to the (2)-nitrogen is an alkyl group. 
As illustrated in Scheme 40, ester 20-2 (R is an alkyl group) can be converted to carbamate 40-2 as described above (see Scheme 11). Catalytic hydrogenation of 40-2 will reduce the nitrile and cleave the CBZ group to provide a diamine of formula 40-3. Acylating 40-3 with a reagent such as CDI, phosgene, or triphosgene in the presence of a base like TEA produces the cyclized ureas of formula 40-4. Deprotection at this stage provides 40-6 where each R2 is H. Alternatively, alkylation of 40-4, such as by deprotonation with a strong base like sodium hydride followed by reaction with an alkylating reagent like an alkyl halide, tosylate or mesylate produces the N,Nxe2x80x2-substituted ureas of formula 40-5. Deprotection then provides 40-6 where each R2 is alkyl. One skilled in the art will recognize that an R1A substituent may be introduced by alkylation of nitrile 20-2. 
Intermediate esters of formula 41-1 (R is an alkyl group) can be prepared by alcoholysis of the cyano group in 40-2 with ethanolic HCl. Reducing the ester group in 41-1, such as with lithium borohydride in THF produces an alcohol of formula 41-2. Catalytic hydrogenation to remove the CBZ group to yield an amine as previously described converts 41-2 to 41-3. Treating 41-3 with a reagent like CDI or other phosgene equivalent in the presence of a base like TEA produces a carbamate of formula 41-4. Deprotection at this stage provides 41-6 where R2 is H. Alternatively, transformation of 41-4 to N-substituted carbamates of formula 41-5 can be achieved by deprotonating 41-4 with a stong base such as sodium hydride in a solvent like DMF, followed by alkylation with a reagent such as an alkyl halide, tosylate or mesylate. Deprotection then converts 41-5 to 41-6 where R2 is alkyl. 
Reaction of a ketoester of formula 42-1 with a chiral amine such as alpha-methylbenzylamine with a suitable aldehyde such as formaldehyde, or reaction of a vinyl ketoester of formula 42-2 with a chiral amine such as alpha-methylbenzylamine with a suitable aldehyde such as formaldehyde, affords a compound of formula 42-3 via a double Mannich reaction. Compound 42-3 is equivalent to 11-1 where d and e are 1, and may be deprotected with a suitable catalyst such as palladium in the presence of hydrogen to give 42-4. In addition, 42-3 could be isolated as a single diastereomer (by selective cyclization or separation of diastereomers), thereby providing 42-4 as a single enantiomer. 
Treatment of a compound of formula 43-1 with a base such as sodium hydride in a solvent such as DMF followed by treatment with diethylcarbonate generates the ethyl ester of compound 43-2 (R is an alkyl group). Deprotection of the amine transforms 43-2 into 43-3. It will be recognized by one skilled in the art that 19-1 is equivalent to 43-3. 
Treatment of a malonic ester of formula 44-1 (R is an alkyl group) with a base such as sodium hydride in a solvent such as DMF and subsequent hydrogenolysis of the benzyl group with hydrogen and a catalyst such as palladium in a suitable solvent such as methanol produces the ester of formula 43-2. Deprotection of the amine generates compounds of formula 43-3. It will be recognized by one skilled in the art that 19-1 is equivalent to 43-3. 
Treatment of a ketone of formula 45-1 with a secondary amine such as piperidine in a suitable solvent such as benzene with removal of water affords an enamine of formula 45-2 (each R is an alkyl group). Alkylation of the enamine with an alpha-haloester such as ethylbromoacetate in a suitable solvent such as benzene or THF using a suitable base such as LDA or NaN(SiMe3)2 affords a ketoester of formula 45-3. Reduction with a mild reducing agent such as sodium borohydride in methanol and subsequent cyclization then affords 26-1. 
Treatment of a ketoester of formula 43-3 (R is an alkyl group) with an iodonium salt such as diphenyliodonium trifluoroacetate in a suitable solvent such as t-butanol generates a ketoester of formula 11-1 where R1 is phenyl. See Synthesis, (9), 1984 p. 709 for a detailed description. 
Treatment of a ketoester of formula 43-3 with an olefin such as acrylonitrile or nitroethylene generates a ketoester of formula 11-1 where R1 is CH2CH2CN or R1 is CH2CH2NO2. 
Treatment of an ester of formula 43-3 (R is an alkyl group) with a base such as sodium hydride in a solvent such as DMF followed by an alkyl halide 48-1 generates a compound of formula 11-1 as illustrated in Scheme 48. 
Treatment of a ketoester of formula 43-2 with allyl bromide and a suitable base such as sodium hydride in a suitable solvent such as DMF affords a ketoester of formula 49-1 (11-1, R2 is allyl). Compound 49-1 may then be converted to 13-4 as described in Scheme 13. Ozonolysis of 13-4 in a suitable solvent such as methylene chloride followed by treatment with a reducing agent such as dimethylsulfide affords an aldehyde of formula 49-2. Oxidation of 49-2 affords a carboxylic acid of formula 49-3. Curtius rearrangement of 49-3, followed by hydrolysis of the intermediate isocyanate affords a primary amine of formula 49-4. Treatment of a compound of formula 49-4 with an isocyanate or carbamate affords a urea of formula 49-5. Deprotection of the nitrogen affords compounds of formula 49-4 (13-5, R1 is CH2NHCONX6X6). Those skilled in the art will recognize that other heterocycles, prepared in previous schemes, could be transformed analogously to the conversion of 13-4 to 49-6. 
Treatment of a compound of formula 49-2 with a primary amine of formula HNX6 affords an imine of formula 50-1. Reduction of a compound of formula 50-1 affords a compound of formula 50-2. Treatment of a compound of formula 50-2 with an acylating agent affords a compound of formula 50-3. Deprotection of the nitrogen affords compounds of formula 50-4 (13-5, R1 is CH2CH2NX6COX6). Those skilled in the art will recognize that other heterocycles, prepared in previous schemes, could be transformed in a manner analogous to the conversion of 49-2 to 50-4. 
Treatment of a compound of formula 49-2 with a reducing agent such as sodium borohydride affords a compound of formula 51-1. Reaction of 51-1 with an acylating agent such as an isocyanate or carbamate affords compounds of formula 51-2. Deprotection of the nitrogen affords compounds of formula 51-3. Those skilled in the art will, recognize that other heterocycles, prepared in previous schemes, could be transformed in a manner analogous to the conversion of 49-2 to 51-3. 
Treatment of a compound of formula 51-1 with a phosphine such as triphenyl phosphine and an azo compound such as diethylazodicarboxylate and an oxindole affords a compound of formula 52-1. Deprotection of the nitrogen affords the compound of formula 52-3. Those skilled in the art will recognize that other heterocycles, prepared in previous schemes, could be transformed in a manner analogous to the conversion of 49-2 to 52-3. 
Treatment of a ketoester of formula 43-3 with a chiral diol and acid catalyst with removal of water in a suitable solvent such as benzene affords a chiral ketal like formula 53-1. Alkylation of 53-1 with an alkyl halide in the presence of a base such as LDA followed by acid-catalyzed hydrolysis of the ketal affords chiral ketoesters of formula 53-2. Ketoester 53-2 is a single enantiomer of 11-1 and may be homologated in a similar fashion to give various heterocycles. 
Treatment of a ketoester of formula 43-3 with a chiral amino acid ester such as valine t-butyl ester affords a chiral enamine of formula 54-1. Alkylation of 54-1 with an alkyl halide in the presence of a base such as LDA followed by acid-catalyzed hydrolysis of the enamine affords chiral ketoesters of formula 53-2. 
Salt formation of 7-6 with a chiral acid affords a mixture of diastereomeric salts of formula 55-1. Crystallization of the diastereomeric salts affords the acid salt of chiral compounds of formula 55-2. Decomposition of the salt 55-2 with base liberates chiral compounds of formula 55-3. This resolution scheme could be applied to the resolution of other HET-bicyclic compounds described above. 
As illustrated in Scheme 56, treatment of 6-4 (P1 is CO2Bn) with an alkyl metal reagent like methyl magnesium bromide affords 56-1. Deprotection as usual then affords 56-2. 
Compounds of formula 57-3 can be prepared from known phthalic or homophthalic anhydrides by methods previously described by Welch, Willard M. (J.Org.Chem 47; 5; 1982; 886-888. J.Org.Chem.; 47; 5; 1982; 886-888) or Machida, Minoru et al. (Heterocycles; 14; 9; 1980; 1255-1258). Alternatively, the analogous phthalimides or homophthalimides of formula 57-1 can be treated with the appropriate hydride reagent (e.g., NaBH4) or organometallic reagent (e.g., methyl Grignard), followed by treatment with sodium or potassium cyanide to produce an intermediate of the formula 57-2. Compounds of formula 57-2 can be converted to compounds of formula 57-3 as previously described by Welch, Willard M. (J.Org.Chem 47; 5; 1982; 886-888). 
As illustrated in Scheme 58, intermediates of formula 58-4 can be prepared in four steps from compounds of formula 7-1. Compounds of formula 7-1 are treated with a suitable reducing agent such as Super Hydride(copyright) in a suitable solvent, preferably THF at a temperature of xe2x88x9220 to 50xc2x0 C., preferably at around 25xc2x0 C. to give compounds of formula 58-1. Amino alcohols of formula 58-1 are then treated with at least two equivalents of methanesulfonyl chloride and at least two equivalents of a suitable base, preferably pyridine in a suitable solvent, preferably pyridine at a temperature of xe2x88x9220 to 50xc2x0C. preferably around 25xc2x0 C. to give intermediates of formula 58-2. Treatment of 58-2 with a strong base, preferably sec-butyllithium at a temperature of around xe2x88x9278xc2x0 C. followed by warming to a temperature of around 25xc2x0 C. affords intermediates of formula 58-3. Removal of the protecting group as described above, transforms 58-3 into 58-4. 
An alternative synthesis of lactam 11-8 is illustrated in Scheme 59. An aldehyde of formula 12-2 can be employed in a reductive amination with an amine and reducing agent, for example sodium triacetoxyborohydride. Subsequent cyclization of the amine with the adjacent ester group affords 11-8. One skilled in the art will recognize that an R1A substituent could have been introduced adjacent to the aldehyde by alkylating aldehyde 12-2 according to well known procedures. 
Aldehydes of formula 60-1 can be prepared by reducing 7-1 with an agent like diisobutylaluminum hydride at a suitable temperature, preferably xe2x88x9278xc2x0 C. to 0xc2x0 C. in a suitable solvent, such as THF, methylene chloride, toluene or ether. This aldehyde may then be converted to amines of the formula 60-2 by the methods described in Scheme 8 to convert 8-3 to 8-5. In addition, an oxime may be formed by treating the aldehyde with hydroxylamine hydrochloride. Reduction of this oxime, such as with Raney-nickel provides 60-2 where R2 is hydrogen. Treatment of this material with phosgene, triphosgene, carbonyl diimidazole, or other equivalent in the presence of a base, preferably a tertiary amine base, provides a route to ureas of formula 8-7. Those skilled in the art will recognize that R2 may have been a group, such as a benzyl or allyl group, which could be cleaved to give 8-7 where R2 is hydrogen.
Alternatively, compounds of the formula 8-7 may be prepared by reducing carbamate protected ester 60-3, for example when R1=CH2-2-Pyr, according to well known reduction techniques to afford aldehyde 60-4 which may then be converted to an amine, as described above, which is then reacted with the carbamate at a suitable temperature to provide 8-7. 
Olefin 61-1 may be prepared by olefinating aldehyde 60-1 with a reagent such as the anion generated upon treating a trialkylphosphono acetate with an appropriate base, such as NaHMDS in a suitable solvent, such as THF. Reduction of the olefin, by methods such as catalytic hydrogenation (see Scheme 11) or conjugate reduction with an agent such as the alkali metal salt of a trialkylborohydride, such as lithium tri-sec-butylborohydride, provides the compounds of formula 61-2. This material is cyclized at elevated temperatures in a reaction inert solvent using cyclization conditions well known to those skilled in the art. Those skilled in the art will recognize that the cyclization reaction may require the addition of a base such as potassium carbonate. Generally the reaction is carried out at reflux in a solvent such as methanol. Deprotection of 61-3 affords compounds of formula 61-5 where R9 and R10=H. Those skilled in the art will recognize that 61-3 can be alkylated under a variety of conditions, such as by treating 61-3 with a strong base, e.g., lithium diisopropylamide or LHMDS in a reaction inert solvent such as THF at a suitable temperature, preferably xe2x88x9278xc2x0 C. The anion generated is treated with alkylating reagents such as alkyl halides or alkyl tosylates, such as methyl iodide, to give 61-4. This process may be repeated to introduce a second substituent. Deprotection affords compunds of formula 61-5. Those skilled in the art will recognize that a R9 substituent can be introduced xcex2 to the lactam by conjugate addition to 61-1, such as would be afforded by the use of an alkyl cuprate reagent. 
An alternate synthesis of 61-3 is shown above. Reduction of ketoamide 62-1, which is equivalent to 10-2 where R9 and R10 are hydrogen, with a reducing agent such sodium borohydride, in an reaction inert solvent such as methanol at a suitable temperature such as 0xc2x0 C. affords alcohol 62-2. The alcohol is reacted under standard elimination conditions well known to those skilled in the art to provide unsaturated lactam 61-3. Suitable elimination conditions include activating the alcohol, such as by converting it to the corresponding tosylate or mesylate, and then treating the activated alcohol with base at a suitable temperature, for instance with 1,8diazabicyclo[5.4.0]undec-7-ene in refluxing toluene, or by deprotonating the amide with a strong base such as LHMDS. The alcohol may also be eliminated at suitable temperatures in the presence of a strong base or strong acid. Those skilled in the art will recognize that these conditions may also cleave the protecting group (P). Reduction of 62-3, by methods such as catalytic hydrogenation (see Scheme 11) or conjugate reduction with an agent such as the alkali metal salt of a trialklyborohydride, like lithium tri-sec-butylborohydride, will then provide 61-3. Those skilled in the art will recognize that a R9 substituent could have been introduced xcex2 to the lactam by conjugate addition of a reagent, such as a cuprate, to the unsaturated lactam. 
Compounds of formula 63-1 are prepared by deprotonating the alcohol with a strong base such as sodium hydride, LHMDS, KHMS or NaHMDS in a suitable solvent such as DMF or THF followed by treatment with an alkylating agent such as an alkyl halide, mesylate or tosylate, for instance, methyl iodide. The product is then deprotected according to methods well known to those skilled in the art to provide 63-2.
Silica gel was used for column chromatography. Melting points were taken on a Buchi 510 apparatus and are uncorrected. Proton and carbon NMR spectra were recorded on a Varian XL-300, UNITYPlus-400, Bruker AC-300, or Bruker AC-250 at 25xc2x0 C. Chemical shifts are expressed in parts per million downfield from trimethylsilane. Particle beam mass spectra (PBMS) were obtained on a Hewlett-Packard 5989A spectrometer using ammonia as the source of chemical ionization. The protonated parent ion is reported as (M+1)+. For initial sample dissolution chloroform or methanol was employed. Atmospheric Pressure Chemical Ionization mass spectra (APcI MS) were obtained on a Platform II by Fisons (now called Micromass Inc.) instrument. They are either run via +APcI (basic method) or xe2x88x92APcI (acid method). The mobile phase is 50:50 H2O:acetonitrile. Either a protonated parent (+APcI) or deprotonated parent ion (xe2x88x92APcI) is observed (reported as (M+1)+ or (Mxe2x88x921)xe2x88x92). For initial sample dissolution, chloroform or methanol was employed. Thermospray mass spectra (TSMS) were obtained on a Trio-1000 by Fisions spectrometer using 0.1 M ammonium acetate in 1/4 water/methanol. The protonated parent ion is reported as (M+1)+. For initial sample dissolution chloroform or methanol were employed. TLC analyses were performed using E. Merck Kieselgel 60 F254 silica plates visualized (after elution with the indicated solvent(s)) by UV, iodine or by staining with 15% ethanolic phosphomolybdic acid or ceric sulfate/ammonium molybdate and heating on a hot plate. The terms xe2x80x9cconcentratedxe2x80x9d and xe2x80x9ccoevaporatedxe2x80x9d refer to removal of solvent at water aspirator pressure on a rotary evaporator with a bath temperature of less than 40xc2x0 C.
The following examples are provided for the purpose of further illustration only and are not intended to be limitations on the disclosed invention.
General Procedure A (Peptide coupling using DEC). A 0.2-0.5 M solution of the primary amine (about 1.0 equivalent) in dichloromethane (or a primary amine hydrochloride and about 1.0-1.3 equivalents of triethylamine) was treated sequentially with about 1.0-1.2 equivalents of the carboxylic acid coupling partner, about 1.5-1.8 equivalents of 1-hydroxy-7-azabenzotriazole (HOAT) and about 1.0-1.2 equivalents 1,2-diethylaminoethyl chloride hydrochloride (DEC) and the mixture was stirred for about 18-48 hours in an ice bath (the ice bath was allowed to warm, thus the reaction mixture was typically held at about 0-20xc2x0 C. for about 4-6 hours and about 20-25xc2x0 C. for the remaining period). The mixture was diluted with ethyl acetate or other solvent as specified, and the resulting mixture washed 1-2 times with 1N NaOH or saturated sodium bicarbonate (the aqueous phase being sometimes back-washed with ethyl acetate), once with brine, dried over Na2SO4, and concentrated giving the crude product which was purified as specified. The carboxylic acid component could be used as the dicyclohexylamine salt in coupling to the primary amine or hydrochloride of the latter, in which case no triethylamine was employed.
General Procedure B (Peptide coupling using EDC). A 0.04-0.5 M solution of the primary amine (about 1.0 equivalent) in dichloromethane (or a primary amine hydrochloride and about 1.0-1.3 equivalents of triethylamine) was treated sequentially with about 1.0-1.2 equivalents of the carboxylic acid coupling partner, about 1.5-1.8 equivalents of 1-hydroxy-7-azabenzotrazole (HOAT), and about 1.0-1.2 equivalents of (stoichiometrically equivalent to the quantity of carboxylic acid) 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and the mixture was stirred for about 18-48 hours in an ice bath (the ice bath was allowed to warm, thus the reaction mixture was typically held at about 0-20xc2x0 C. for about 4-6 hours and about 20-25xc2x0 C. for the remaining period). The mixture was diluted with chloroform or other solvent as specified, and the resulting mixture washed twice with 10% HCl (if the product does not contain a basic functionality that would make the compound soluble in aqueous acidic solution), twice with saturated sodium bicarbonate solution, 1-2 times with brine, dried over anhydrous magnesium sulfate, and concentrated giving the crude product which was purified as specified. The carboxylic acid component could be used as the dicyclohexylamine salt in coupling to the primary amine or hydrochloride of the latter, in which case no triethylamine was employed.
General Procedure C. (Cleavage of a t-BOC-protected amine using concentrated HCl). The t-Boc amine was dissolved in a minimum volume of ethanol and the resulting solution was cooled to about 0xc2x0 C. and concentrated HCl (typically about 1-4 mL per mmol amine) was added and the reaction was warmed to room temperature and stirred for about 1-2.5 hours (the time required for complete disappearance of the starting material to a more polar product as judged by TLC). The resulting solution or suspension was concentrated, and the residue coevaporated several times with added ethanol to give the free amine which was used without further purification or purified as specified.
General Procedure D. (Cleavage of a t-BOC-protected amine using TFA). Trifluoroacetic acid (usually at about 0-25xc2x0 C.) was added to the t-Boc amine (typically about 10 mL per mmol amine) neat or dissolved in a minimum volume of dichloromethane and the resulting solution was stirred at about 0xc2x0 C. or at room temperature for 0.25-2 hours (the time required for complete disappearance of the starting material to a more polar product as judged by TLC). The resulting solution or suspension was concentrated, and the residue coevaporated several times with added methylene chloride. The residue was then dissolved in ethyl acetate and washed twice with 1N NaOH and once with brine. The organic phase was then dried over Na2SO4 and evaporated to give the free amine which was used without further purification or purified as specified.
General Procedure E. (Cleavage of a benzylprotected amine using 10% palladium on carbon). The benzyl amine, ethanol (typically about 1 mL per every 0.03-0.08 mmol of amine), and 10% palladium on carbon (typically about 20-100% of the weight of the amine used) were combined and hydrogenated at about 40-50 psi hydrogen on a Parr(copyright) shaker overnight. The mixture was then filtered through a bed of Celite(copyright). The Celite(copyright) was washed with ethanol, and the filtrate was concentrated in vacuo to give the de-benzylated amine which was used without further purification or purified as specified.
General Procedure F. (Cleavage of a CBZ-protected amine using 10% palladium on carbon) The CBZ amine, ethanol (typically about 1 mL per every 0.03-0.08 mmol of amine), and 10% palladium on carbon (typically about 20-100% of the weight of the amine used) were combined and hydrogenated at about 40-50 psi hydrogen on a Parr(copyright) shaker overnight. The mixture was then filtered through a bed of Celite(copyright). The Celite(copyright) was washed with ethanol, and the filtrate was concentrated in vacuo to give the de-benzylated amine which was used without further purification or purified as specified.